tools/power/turbostat: Add support for Xe sysfs knobs

Xe graphics driver uses different graphics sysfs knobs including
   /sys/class/drm/card0/device/tile0/gt0/gtidle/idle_residency_ms
   /sys/class/drm/card0/device/tile0/gt0/freq0/cur_freq
   /sys/class/drm/card0/device/tile0/gt0/freq0/act_freq
   /sys/class/drm/card0/device/tile0/gt1/gtidle/idle_residency_ms
   /sys/class/drm/card0/device/tile0/gt1/freq0/cur_freq
   /sys/class/drm/card0/device/tile0/gt1/freq0/act_freq

Plus that,
   /sys/class/drm/card0/device/tile0/gt<n>/gtidle/name
returns either gt<n>-rc or gt<n>-mc. rc is for GFX and mc is SA Media.

Enhance turbostat to prefer the Xe sysfs knobs when they are available.
Export gt<n>-rc via BIC_GFX_rc6/BIC_GFXMHz/BIC_GFXACTMHz.
Export gt<n>-mc via BIC_SMA_mc6/BIC_SMAMHz/BIC_SMAACTMHz.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>