drm/mali-dp: Rotated planes need a larger pitch size.

Rotated planes need a pitch size that is aligned to 8 bytes
for older DP500 and DP550 and at least 64 bytes for DP650. Replace
the malidp_hw_pitch_valid() function with one that calculates
the correct pitch alignment to take into account rotation.

Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>