si4708: minor simplification

Change-Id: I225382280505f21cfe8bece213ce4d9c5bc2983f
Update patches: fix DECIDE_TEXTURE_TARGET

The DECIDE_TEXTURE_TARGET hack wasn't correctly handling the
BufferRejecter that was added in JB and this resulted in various
graphical corruption.

Change-Id: I9499940402f16b71bc6846542e07f553b0aa31bf