drm/i915/guc: Use context hints for GT frequency

Allow user to provide a low latency context hint. When set, KMD
sends a hint to GuC which results in special handling for this
context. SLPC will ramp the GT frequency aggressively every time
it switches to this context. The down freq threshold will also be
lower so GuC will ramp down the GT freq for this context more slowly.
We also disable waitboost for this context as that will interfere with
the strategy.

We need to enable the use of SLPC Compute strategy during init, but
it will apply only to contexts that set this bit during context
creation.

Userland can check whether this feature is supported using a new param-
I915_PARAM_HAS_CONTEXT_FREQ_HINT. This flag is true for all guc submission
enabled platforms as they use SLPC for frequency management.

The Mesa usage model for this flag is here -
https://gitlab.freedesktop.org/sushmave/mesa/-/commits/compute_hint



v2: Rename flags as per review suggestions (Rodrigo, Tvrtko).
Also, use flag bits in intel_context as it allows finer control for
toggling per engine if needed (Tvrtko).

v3: Minor review comments (Tvrtko)

v4: Update comment (Sushma)

Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Sushma Venkatesh Reddy <sushma.venkatesh.reddy@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Ivan Briano <ivan.briano@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/20240306012759.204938-1-vinay.belgaumkar@intel.com