msm: ipa: Add support in ipa-mhi driver for cv2x

Only one pair of MHI ep's are supported till now.
With respect to auto-pcie use case requirement
we need to support one more MHI ep pair for cv2x.
Modify ipa-mhi driver to support additional mhi ep pair.

Change-Id: I301dc7c46c6bfcc995db5a6a56c677481588d20b
Signed-off-by: Mohammed Javid <mjavid@codeaurora.org>