usb: hsic: Add support for seperate Async IRQ for LPM functionality

On newer platforms USB HSIC core is having seperate IRQ line for getting
core out of LPM. This change adds support for it and enable Async IRQ only
when USB HSIC core is in low power mode.

CRs-fixed: 763212
Change-Id: I808473c2f51e8183484942c6cfafbfca77663e1a
Signed-off-by: Danny Segal <dsegal@codeaurora.org>
Signed-off-by: Mayank Rana <mrana@codeaurora.org>