[media] s5p-fimc: Remove unused platform data structure fields

alignment, fixed_phy_vdd and phy_enable fields are now unused
so removed them. The data alignment is now derived directly
from media bus pixel code, phy_enable callback has been replaced
with direct function call and fixed_phy_vdd was dropped in commit
438df3eb
"[media] s5p-csis: Handle all available power supplies".

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>