drm/xe: Add MI_MATH and ALU instruction definitions

The command streamer implements an Arithmetic Logic Unit (ALU)
which supports basic arithmetic and logical operations on two
64-bit operands. Access to this ALU is thru the MI_MATH command
and sixteen General Purpose Register (GPR) 64-bit registers,
which are used as temporary storage.

Bspec: 45737, 60236 # MI
Bspec: 45525, 60132 # ALU
Bspec: 45533, 60309 # GPR
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250304162307.1866-1-michal.wajdeczko@intel.com