x86: boot - fix sparse warnings

Impact: make global variables static

Fix these sparse warnings:

 arch/x86/boot/video.c:233:3: warning: symbol 'saved' was not declared. Should it be static?
 arch/x86/boot/video-vga.c:37:13: warning: symbol 'video_vga' was not declared. Should it be static?
Signed-off-by: Hannes Eder <hannes@hanneseder.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/boot/video-vga.c

@@ -34,7 +34,7 @@ static struct mode_info cga_modes[] = {
 	{ VIDEO_80x25,  80, 25, 0 },
 };
 
-__videocard video_vga;
+static __videocard video_vga;
 
 /* Set basic 80x25 mode */
 static u8 vga_set_basic_mode(void)
@@ -259,7 +259,7 @@ static int vga_probe(void)
 	return mode_count[adapter];
 }
 
-__videocard video_vga = {
+static __videocard video_vga = {
 	.card_name	= "VGA",
 	.probe		= vga_probe,
 	.set_mode	= vga_set_mode,

arch/x86/boot/video.c

@@ -226,7 +226,7 @@ static unsigned int mode_menu(void)
 
 #ifdef CONFIG_VIDEO_RETAIN
 /* Save screen content to the heap */
-struct saved_screen {
+static struct saved_screen {
 	int x, y;
 	int curx, cury;
 	u16 *data;