aco: Fix uniform i2i64.
Fixes 240 failing test cases in dEQP-VK.spirv_assembly which were failing due to a bad s_ashr_i32 instruction. This commit fixes the instruction format along with the definitions of the instruction.
Fixes: 11f43caa Cc: 19.3 mesa-stable@lists.freedesktop.org Signed-off-by: Timur Kristóf timur.kristof@gmail.com