HummingBoard rev 3.0 support

Added features and fixes to get HummingBoard rev 3.0 up and running. This patches fixes and adds -
1. USB OTG ID is internally pulled down and doesn't use GPIO_1 pad
2. Added pcie support
3. Added sgtl5k audio support
4. Added 26 pin header GPIO pin definition (can be accessed via sysfs)
5. Infrared now uses gpio3,5 (instead of gpio1,2 as in C1)
6. Camera interface registration is removed from microsom file and added to HB carrier

Signed-off-by: Rabeeh Khoury <rabeeh@solid-run.com>
Mic gain is 2 bits

This fixes overflow in microphone gain bits

Signed-off-by: Rabeeh Khoury <rabeeh@solid-run.com>