etnaviv: Unified uniforms support

etnaviv: Unified uniforms support

GC3000 has changed from a separate store for VS and PS uniforms
to a single, unified one. There is backwards compatibilty functionalty,
however this does not work correctly together with ICACHE.

This patch adds explicit support, although in the simplest way possible:
the PS/VS uniforms split is still fixed and hardcoded. It should
make no difference on hardware that does not have unified uniform
memory.

Signed-off-by: Wladimir J. van der Laan <laanwj@gmail.com>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>