leds-pca955x: Remove the unused function pca95xx_num_led_regs()

The function pca95xx_num_led_regs() is defined in the leds-pca955x.c
file, but not called elsewhere, so delete this unused function.

drivers/leds/leds-pca955x.c:149:19: warning: unused function 'pca95xx_num_led_regs'.

Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=2411


Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Pavel Machek <pavel@ucw.cz>