board/ti/beagle/beagle.c: Fix build warnings

Fix:
beagle.c:257:13: warning: function declaration isn't a prototype
[-Wstrict-prototypes]
beagle.c:257:13: warning: function declaration isn't a prototype
[-Wstrict-prototypes]

Also make beagle_dvi_pup() checkpatch clean, fix:
ERROR: open brace '{' following function declarations go on the
next line

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Cc: Tom Rini <trini@ti.com>

board/ti/beagle/beagle.c

@@ -254,7 +254,8 @@ void beagle_display_init(void)
 /*
  * Enable DVI power
  */
-static void beagle_dvi_pup() {
+static void beagle_dvi_pup(void)
+{
 	uchar val;
 
 	switch (get_board_revision()) {