ENGR00160061 - MXC HDMI: Optimize HDMI clock management

ENGR00160061 - MXC HDMI: Optimize HDMI clock management

- Ensure HDMI clocks are disabled when leaving HDMI core probe function.
- Create HDMI core api to allow HDMI sub-drivers to init, enable, and
disable the HDMI IRQ.  Required to optimally manage HDMI clocks,
allow IAHB to be disabled, and still have video and audio sub-drivers
able to receive interrupts.
- Update code to adjust for decoupled ISFR and IAHB clocks.
- Disable IAHB clocks whenever HDMI not plugged in.

Signed-off-by: Danny Nold <dannynold@freescale.com>