Camera: Add torch brightness control keys.

1.FLASH_INFO_STRENGTH_MAXIMUM_LEVEL : Number of brightness levels.
2.FLASH_INFO_STRENGTH_DEFAULT_LEVEL : Default brightness level to be set
via setTorchBrightnessLevel API.

bug: 200174275
Change-Id: Iab35bc3cbc8c8ede0b1729f45be4b8ba1b3fed78
1 file changed