usb: host: xhci-plat: Fix interrupt storm issue in host mode

During xhci_suspend driver disables interrupt, clears HW_ACCESSIBLE and
halts the controller. There is still a possibility of a pending interrupt
before controller is halted which may get fired once interrupt is enabled
again in xhci_suspend. This results in interrupt storm as HCD irq handler
returns with IRQ_NONE due to HW_ACCESSIBLE is not set.

Fix this by disabling the irq before calling xhci_suspend and enable it
back after resume completion.

Change-Id: I68fbbb76eee533a4432e19443e875b981d316453
Signed-off-by: Chandana Kishori Chiluveru <cchiluve@codeaurora.org>