drm/xe/pmu: Remove PMU from Xe till uapi is finalized

PMU uapi is likely to change in the future. Till the uapi is finalized,
remove PMU from Xe. PMU can be re-added after uapi is finalized.

v2: Include xe_drm.h in xe/tests/xe_dma_buf.c (Francois)

Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Acked-by: Aravind Iddamsetty <aravind.iddamsetty@linux.intel.com>
Acked-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Acked-by: José Roberto de Souza <jose.souza@intel.com>
Acked-by: Mateusz Naklicki <mateusz.naklicki@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>