drm/i915/bxt: Fix HDMI DPLL configuration

drm/i915/bxt: Fix HDMI DPLL configuration

a277ca7dc01d should've been a no-functional-change commit, but it
removed the initialization of the dpll_hw_state for HDMI outputs,
resulting in state mismatches and a failed modeset with blank
screen. Fix this by reinstating the dpll_hw_state initialization.

v2:
- Make bxt_ddi_hdmi_set_dpll_hw_state() static.

Cc: Manasi Navare <[email protected]>
Cc: Ander Conselvan de Oliveira <[email protected]>
Cc: Durgadoss R <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Fixes: a277ca7dc01d ("drm/i915: Split bxt_ddi_pll_select()")
Signed-off-by: Imre Deak <[email protected]>
Reviewed-by: Ander Conselvan de Oliveira <[email protected]>
Link: http://patchwork.freedesktop.org/patch/msgid/[email protected]
(cherry picked from commit a04139c4cf289119cdfb6081af602f7a452fb7c2)
Signed-off-by: Jani Nikula <[email protected]>