usb: xhci-msm-hsic: Set the interrupt moderation to 4000

Higher value allows xhci core to moderate interrupts resulting
in fewer interrupts from xhci core. This may result in better
overall power consumption during peak throughput.

Change-Id: I1c07254b477e56804cbd3f5e666900786ef05619
Signed-off-by: Vamsi Krishna <vskrishn@codeaurora.org>