drm: mali-dp: Check for sufficient address space

If the device-tree 'reg' node doesn't reserve enough
space for the DP, fail to bind.

Reviewed-by: Brian Starkey <brian.starkey@arm.com>
Signed-off-by: Mihail Atanassov <mihail.atanassov@arm.com>
[renamed added function to malidp_has_sufficient_address_space]
Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>