Revert "drm/i915/tgl/dsi: Gate the ddi clocks after pll mapping"

This reverts commit 991d9557 ("drm/i915/tgl/dsi: Gate the ddi clocks
after pll mapping"). The Bspec was updated recently with the pll ungate
sequence similar to that of icl dsi enable sequence. Hence reverting.

Bspec: 49187
Fixes: 991d9557

 ("drm/i915/tgl/dsi: Gate the ddi clocks after pll mapping")
Cc: <stable@vger.kernel.org> # v5.4+
Signed-off-by: Vandita Kulkarni <vandita.kulkarni@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211109120428.15211-1-vandita.kulkarni@intel.com