drm/amdgpu:impl RREG32 no kiq version

some registers are PF & VF copy, and we can safely use
mmio method to access them.

and sometime we are forbid to use kiq to access registers
for example in INTR context.

we need a MACRO that always disable KIQ for regs accessing

Signed-off-by: Monk Liu <Monk.Liu@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Xiangliang Yu <Xiangliang.Yu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>