drm/arm/malidp: Enable/disable interrupts in runtime pm

Display and scaling engine interrupts need to be disabled when the
runtime pm invokes malidp_runtime_pm_suspend(). Conversely, they
need to be enabled in malidp_runtime_pm_resume().

This patch depends on:
https://lkml.org/lkml/2017/5/15/695



Reported-by: Alexandru-Cosmin Gheorghe <Alexandru-Cosmin.Gheorghe@arm.com>
Signed-off-by: Alexandru-Cosmin Gheorghe <Alexandru-Cosmin.Gheorghe@arm.com>
Signed-off-by: Ayan Kumar Halder <ayan.halder@arm.com>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>