drm/i915/pcode: Extend pcode functions for multiple gt's

Each gt contains an independent instance of pcode. Extend pcode functions
to interface with pcode on different gt's. To avoid creating dependency of
display functionality on intel_gt, pcode function interfaces are exposed in
terms of uncore rather than intel_gt. Callers have been converted to pass
in the appropritate (i915 or intel_gt) uncore to the pcode functions.

v2: Expose pcode functions in terms of uncore rather than gt (Jani/Rodrigo)
v3: Retain previous function names to eliminate needless #defines (Rodrigo)
v4: Move out i915_pcode_init() to a separate patch (Tvrtko)
    Remove duplicated drm_err/drm_dbg from intel_pcode_init() (Tvrtko)

Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220519085732.1276255-2-tvrtko.ursulin@linux.intel.com
[tursulin: fixup merge conflict]