backlight: ld9040: Staticize local variable gamma_table

Fix the following sparse warnings:

  drivers/video/backlight/ld9040_gamma.h:172:3: warning: symbol 'gamma_table' was not declared. Should it be static?
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/video/backlight/ld9040_gamma.h

@@ -169,7 +169,9 @@ static const unsigned int ld9040_22_50[] = {
 
 struct ld9040_gamma {
 	unsigned int *gamma_22_table[MAX_GAMMA_LEVEL];
-} gamma_table = {
+};
+
+static struct ld9040_gamma gamma_table = {
 	.gamma_22_table[0] = (unsigned int *)&ld9040_22_50,
 	.gamma_22_table[1] = (unsigned int *)&ld9040_22_70,
 	.gamma_22_table[2] = (unsigned int *)&ld9040_22_80,