RC model has these parameters that correspond with each of
15 ranges of RC buffer threshold value in the RC model.
The three elements are range_min_qp, range_max_qp and
range_bpg_offset.

Add the Rate Control range values for eDP/MIPI and DP case.
The actual values are calculated usung a helper function.
This patch adds the shifts to registers where the value will
be written during atomic commit.

v2:
- Use _MMIO_PIPE() instead of _MMIO(_PICK()) (Manasi)
- Combine shifts (Manasi)

Cc: Jose Souza <jose.souza@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: NAnusha Srivatsa <anusha.srivatsa@intel.com>
Reviewed-by: NManasi Navare <manasi.d.navare@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1531861861-10950-4-git-send-email-anusha.srivatsa@intel.com