power: supply: Make bd9995x_chip_reset static

Fix the following sparse warning:

drivers/power/supply/bd99954-charger.c:1028:6: warning: symbol 'bd9995x_chip_reset' was not declared.

The bd9995x_chip_reset() has only one call site within bd99954-charger.c
It should be static

Fixes: 0902f8366491 ("power: supply: Support ROHM bd99954 charger")
Reported-by: Hulk Robot <[e-mail]>
Signed-off-by: Samuel Zou <[e-mail]>
Reviewed-by: Matti Vaittinen <[e-mail]>
Signed-off-by: Sebastian Reichel <[e-mail]>

drivers/power/supply/bd99954-charger.c

···
 	return 0;
 }
 
-void bd9995x_chip_reset(void *bd)
+static void bd9995x_chip_reset(void *bd)
 {
 	__bd9995x_chip_reset(bd);
 }