leds: flash: Set variables mvflash_{3,4}ch_regs storage-class-specifier to static

Smatch reports:

  drivers/leds/flash/leds-qcom-flash.c:103:18: warning:
    symbol 'mvflash_3ch_regs' was not declared. Should it be static?
  drivers/leds/flash/leds-qcom-flash.c:115:18: warning:
    symbol 'mvflash_4ch_regs' was not declared. Should it be static?

These variables are only used locally, so it should be static.

Signed-off-by: Tom Rix <trix@redhat.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20230317191341.1670660-1-trix@redhat.com