drm/i915/gen11: Program ICL_DPCLKA_CFGCR0 according to PHY

Although the register name implies that it operates on DDI's,
DPCLKA_CFGCR0_ICL actually needs to be programmed according to the PHY
that's in use.  I.e., when using EHL's DDI-D on combo PHY A, the bits
described as "port A" in the bspec are what we need to set.  The bspec
clarifies:

        "[For EHL] DDID clock tied to DDIA clock, so DPCLKA_CFGCR0 DDIA
        Clock Select chooses the PLL for both DDIA and DDID and drives
        port A in all cases."

Also, since the CNL DPCLKA_CFGCR0 bit defines are still port-based, we
create separate ICL-specific defines that accept the PHY rather than
trying to share the same bit definitions between CNL and ICL.

v5: Make icl_dpclka_cfgcr0_clk_off() take phy rather than port.  When
    splitting the original patch the hunk to handle this wound up too
    late in the series.  (Sparse)

v6: Since we're already changing this code,
    s/DPCLKA_CFGCR0_ICL/ICL_DPCLKA_CFGCR0/ for consistency.  (Jose)

Bspec: 33148
Cc: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190709183934.445-3-matthew.d.roper@intel.com