Remove unnecessary binder_call from cameraserver

This is a follow-up to 93391686
which added both
hal_client_domain(cameraserver, hal_graphics_allocator) and
binder_call(cameraserver, hal_graphics_allocator). The latter
binder_call rule is no longer needed because it is automatically
granted by virtue of cameraserver being marked as a client of
Graphics Allocator HAL --
see 49274721.

Test: Take a photo (both HDR and conventional) using Google Camera
Test: Record video using Google Camera
Test: Record slow motion video using Google Camera
Test: No denials to do with cameraserver and hal_graphics_allocator*
Bug: 34170079
Change-Id: If93fe310fa62923b5107a7e78d158f6e4b4d0b3a