R600/SI: add VOP mapping functions

Make it possible to map between e32 and e64 encoding opcodes.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Tom Stellard <thomas.stellard@amd.com>
R600/SI: Add promotion of e32 to e64 in operand folding

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Tom Stellard <thomas.stellard@amd.com>