backlight: qcom-spmi-wled: Add missing break in wled_flash_led_prepare()

Add the missing break statement in wled_flash_led_prepare()
without which querying maximum current for flash/torch devices
is broken.

Change-Id: I79e21f464d677863cb2a6d8c71fe7c8152e536e9
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>