Add PHY specific display initialization sequence as per BSpec.

Note that the PHY initialization/uninitialization are done
at their current place only for simplicity, in a future patch - when more
of the runtime PM features will be enabled - these will be moved to
power well#1 and modeset encoder enabling/disabling hooks respectively.

The call to uninitialize the PHY during system/runtime suspend will be
added later in this patchset.

v1: Added function definitions in header files
v2: Imre's review comments addressed
- Moved CDCLK related definitions to i915_reg.h
- Removed defintions for CDCLK frequency
- Split uninit_cdclk() by adding a phy_uninit function
- Calculate freq and decimal based on input frequency
- Program SSA precharge based on input frequency
- Use wait_for 1ms instead 200us udelay for DE PLL locking
- Removed initial value for divider, freq, decimal, ratio.
- Replaced polling loops with wait_for
- Parameterized latency optim setting
- Fix the parts where DE PLL has to be disabled.
- Call CDCLK selection from mode set

v3: (imre)
- add note about the plan to move the cdclk/phy init to a better place
- take rps.hw_lock around pcode access
- fix DDI PHY timeout value
- squash in Vandana's "PORT_CL2CM_DW6_A BUN fix",
  "DDI PHY programming register defn", "Do ddi_phy_init always",
- move PHY register macros next to the corresponding CHV/VLV macros
- move DE PLL register macros here from another patch since they are
  used here first
- add BXT_ prefix to CDCLK flags
- s/COMMON_RESET/COMMON_RESET_DIS/ and clarify related code comments
- fix incorrect read value for the RMW of BXT_PHY_CTL_FAMILY_DDI
- fix using GT_DISPLAY_EDP_POWER_ON vs. GT_DISPLAY_DDI_POWER_ON
  when powering on DDI ports
- fix incorrect port when setting BXT_PORT_TX_DW14_LN for DDI ports
- add missing masking when programming CDCLK_FREQ_DECIMAL
- add missing powering on for DDI-C port, rename OCL2_LDOFUSE_PWR_EN
  to OCL2_LDOFUSE_PWR_DIS to reduce confusion
- add note about mismatch with bspec in the PORT_REF_DW6 fields
- factor out PHY init code to a new function, so we can call it for
  PHY1 and PHY0, instead of open-coding the same

v4: (ville)
- split the CDCLK/PHY parts into two patches, update commit message
  accordingly
- use the existing dpio_phy enum instead of adding a new one for the
  same purpose
- flip the meaning of PHYs so that PHY_A is PHY1 and PHY_BC is PHY0 to
  better match CHV
- s/BXT_PHY/_BXT_PHY/
- use _PIPE for _BXT_PHY instead of open-coding it
- drop _0_2_0_GTTMMADR suffix from BXT_P_CR_GT_DISP_PWRON
- define GT_DISPLAY_POWER_ON in a more standard way
- make a note that the CHV ConfigDB also disagrees about GRC_CODE field
  definitions
- fix lane optimization refactoring fumble from v3
- add per PHY uninit functions to match the init counterparts

Signed-off-by: Vandana Kannan <vandana.kannan@intel.com> (v2)
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>