shell: improve parse_hex() to use new stdio implementation

source/shell/flash.c

@@ -23,15 +23,8 @@ static void parse_hex(FILE *fp, char *buf, size_t len)
 	for (i = 0; i < len; ++i) {
 		memset(s, '\0', 3);
 
-		while ((s[0] = getc(fp)) && !isxdigit(s[0]))
-			putchar(s[0]);
-
-		putchar(s[0]);
-
-		while ((s[1] = getc(fp)) && !isxdigit(s[1]))
-			putchar(s[1]);
-
-		putchar(s[1]);
+		while ((s[0] = getc(fp)) && !isxdigit(s[0]));
+		while ((s[1] = getc(fp)) && !isxdigit(s[1]));
 
 		*buf++ = strtoul(s, NULL, 16);
 	}