gfx: drv: save the pfit/hdmi/mipi regs along with the rest of pipe regs

gfx: drv: save the pfit/hdmi/mipi regs along with the rest of pipe regs

Move the saving of these registers where the rest of pipe regs are
saved. This should make the next patch easier to parse and make it
clearer what is saved for each pipe.

The access order of these registers will move before the palette
register saving, but as none of these registers have a side-effect when
reading, this shouldn't matter.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>