drm/amdkfd: remove gfx 12 trap handler page size cap

[ Upstream commit cd82f29e ]

GFX 12 does not require a page size cap for the trap handler because
it does not require a CWSR work around like GFX 11 did.

Signed-off-by: Jonathan Kim <jonathan.kim@amd.com>
Reviewed-by: David Belanger <david.belanger@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>