get_maintainer: fix perl 5.22/5.24 deprecated/incompatible "\C" use

from linux commit ce8155f7a3d5:

Perl 5.22 emits a deprecated message when "\C" is used in a regex.  Perl
5.24 will disallow it altogether.

Fix it by using [A-Z] instead of \C.

>From linux adapted to U-Boot by:
Signed-off-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>

scripts/get_maintainer.pl

@@ -298,7 +298,7 @@ sub read_maintainers {
     while (<$maint>) {
 	my $line = $_;
 
-	if ($line =~ m/^(\C):\s*(.*)/) {
+	if ($line =~ m/^([A-Z]):\s*(.*)/) {
 	    my $type = $1;
 	    my $value = $2;
 
@@ -533,7 +533,7 @@ sub range_is_maintained {
 
     for (my $i = $start; $i < $end; $i++) {
 	my $line = $typevalue[$i];
-	if ($line =~ m/^(\C):\s*(.*)/) {
+	if ($line =~ m/^([A-Z]):\s*(.*)/) {
 	    my $type = $1;
 	    my $value = $2;
 	    if ($type eq 'S') {
@@ -551,7 +551,7 @@ sub range_has_maintainer {
 
     for (my $i = $start; $i < $end; $i++) {
 	my $line = $typevalue[$i];
-	if ($line =~ m/^(\C):\s*(.*)/) {
+	if ($line =~ m/^([A-Z]):\s*(.*)/) {
 	    my $type = $1;
 	    my $value = $2;
 	    if ($type eq 'M') {
@@ -600,7 +600,7 @@ sub get_maintainers {
 
 	    for ($i = $start; $i < $end; $i++) {
 		my $line = $typevalue[$i];
-		if ($line =~ m/^(\C):\s*(.*)/) {
+		if ($line =~ m/^([A-Z]):\s*(.*)/) {
 		    my $type = $1;
 		    my $value = $2;
 		    if ($type eq 'X') {
@@ -615,7 +615,7 @@ sub get_maintainers {
 	    if (!$exclude) {
 		for ($i = $start; $i < $end; $i++) {
 		    my $line = $typevalue[$i];
-		    if ($line =~ m/^(\C):\s*(.*)/) {
+		    if ($line =~ m/^([A-Z]):\s*(.*)/) {
 			my $type = $1;
 			my $value = $2;
 			if ($type eq 'F') {
@@ -917,7 +917,7 @@ sub find_first_section {
 
     while ($index < @typevalue) {
 	my $tv = $typevalue[$index];
-	if (($tv =~ m/^(\C):\s*(.*)/)) {
+	if (($tv =~ m/^([A-Z]):\s*(.*)/)) {
 	    last;
 	}
 	$index++;
@@ -931,7 +931,7 @@ sub find_starting_index {
 
     while ($index > 0) {
 	my $tv = $typevalue[$index];
-	if (!($tv =~ m/^(\C):\s*(.*)/)) {
+	if (!($tv =~ m/^([A-Z]):\s*(.*)/)) {
 	    last;
 	}
 	$index--;
@@ -945,7 +945,7 @@ sub find_ending_index {
 
     while ($index < @typevalue) {
 	my $tv = $typevalue[$index];
-	if (!($tv =~ m/^(\C):\s*(.*)/)) {
+	if (!($tv =~ m/^([A-Z]):\s*(.*)/)) {
 	    last;
 	}
 	$index++;
@@ -971,7 +971,7 @@ sub get_maintainer_role {
 
     for ($i = $start + 1; $i < $end; $i++) {
 	my $tv = $typevalue[$i];
-	if ($tv =~ m/^(\C):\s*(.*)/) {
+	if ($tv =~ m/^([A-Z]):\s*(.*)/) {
 	    my $ptype = $1;
 	    my $pvalue = $2;
 	    if ($ptype eq "S") {
@@ -1030,7 +1030,7 @@ sub add_categories {
 
     for ($i = $start + 1; $i < $end; $i++) {
 	my $tv = $typevalue[$i];
-	if ($tv =~ m/^(\C):\s*(.*)/) {
+	if ($tv =~ m/^([A-Z]):\s*(.*)/) {
 	    my $ptype = $1;
 	    my $pvalue = $2;
 	    if ($ptype eq "L") {
@@ -1072,7 +1072,7 @@ sub add_categories {
 		if ($name eq "") {
 		    if ($i > 0) {
 			my $tv = $typevalue[$i - 1];
-			if ($tv =~ m/^(\C):\s*(.*)/) {
+			if ($tv =~ m/^([A-Z]):\s*(.*)/) {
 			    if ($1 eq "P") {
 				$name = $2;
 				$pvalue = format_email($name, $address, $email_usename);