Revert "usb: xhci: Set interrupt moderation for host mode to 4000(1ms)"

This reverts commit 32e9bf0e
("usb: xhci: Set interrupt moderation for host mode to 4000(1ms)") to
restore default imod value in XHCI driver as IMOD value is now passed
from DT for required targets.

CRs-fixed: 1019219
Change-Id: I8bc3c2217cafde0e767671e192f6563f89712575
Signed-off-by: Manu Gautam <mgautam@codeaurora.org>