omapdss: HDMI: add HDMI wrapper IRQ flags

Add flags for the interrupts present in HDMI wrapper block, these will be used
to configure HDMI_IRQENABLE_SET/CLEAR and HDMI_IRQSTATUS registers.

Signed-off-by: Archit Taneja <archit@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>