msm: kgsl: Remove legacy device matching for the adreno device

Device tree is the new normal for all supported targets.  Remove
legacy matching and depend entirely on of_match_device().

Change-Id: Ic0dedbad97b9198e4434e6c74d8b2fc5818b3ce1
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>