msm: mdss: Export rotator interrupt and share rotator smmu

Existing rotator block is serviced by fbdev rotator driver.
This change enables usermode to use external v4l2 rotator driver by
exporting rotator interrupts (WB0 & WB1) thru interrupt domain,
and share smmu access for writeback and rotator.

mdp_irq_export is only set if has_separate_rotator is specified
in device tree and MDSS version is prior to 2.0.

mdp_irq_export is set to zero otherwise, and will effectively
disable mdp irq export and will introduce only minimal overhead
to interrupt processing.  This is the default behaviour for
MDSS newer than 2.0.

CRs-Fixed: 1017182
Signed-off-by: Alan Kwong <akwong@codeaurora.org>
Change-Id: If634894768b02d124ceab071a9eca1c36f258600