p970: dont use fence sync

Fence sync is known to cause issues with the GPU
blobs that we are currently using. Disabling it
vastly improves performance on P970.

This affects other OMAP3 devices (I9003, Encore)
also which are using the same kernel and GPU binaries
as that of P970.

Change-Id: If29315f69c575c0ac0dfc9a4c7354dfedf0fbbf8
p970: use HAS_CONTEXT_PRIORITY

Used on OMAP4 and Improves performance on OMAP3.

Change-Id: I04a4ce73f607306d78565a6f4fbbf7ab2769daa0
Merge branch 'cm-10.1' into martincz