This interrupt is enabled during RPS initialization, and
now needs to be done by SLPC code. It allows ARAT timer
expiry interrupts to get forwarded to GuC.

v2: Fix comment (Matthew Brost)
v3: checkpatch()
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210730202119.23810-11-vinay.belgaumkar@intel.com