drm/amdkfd: Fix ASIC name typos

Three misspelled ASICs in comments here, so fix the spelling

Signed-off-by: Kent Russell <kent.russell@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>