drm/xe: Add vram frequency sysfs attributes

drm/xe: Add vram frequency sysfs attributes

Add vram frequency sysfs attributes under the below hierarchy;

/device/tile#/memory/freq0
			|-max_freq
			|-min_freq

v2: Drop "vram" from attribute names (Rodrigo)

v3: Add documentation for new sysfs (Riana)
    Drop prefix from XEHP_PCODE_FREQUENCY_CONFIG (Riana)

v4: Create sysfs under tile#/freq0 after removal of
    physical_memsize attrbute

v5: Revert back to creating sysfs under tile#/memory/freq0
    Remove definition of GT_FREQUENCY_MULTIPLIER (Rodrigo)

v6: Rename attributes to max/min_freq (Anshuman)
    Fix review comments (Rodrigo)

v7: Make documentation more verbose
    Move sysfs to separate file (Anshuman)

v8: Fix platform specific conditions and add kernel doc (Anshuman)
    Fix typos and remove redundant headers (Riana)

v9: Fix typo (Riana)
    Change function name to include "sysfs" (Lucas)

Signed-off-by: Sujaritha Sundaresan <sujaritha.sundaresan@intel.com>
Reviewed-by: Anshuman Gupta <anshuman.gupta@intel.com>
Link: https://lore.kernel.org/r/20240109110418.2065101-1-sujaritha.sundaresan@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>