f_gsi: Bail out if suspend event is pending before enabling data path

When cable is connected, following sequence is expected to happen:
set_alt() ->ipa_connect_channels()->ipa_data_path(). As part of
ipa_data_path(), endpoints will be enabled and start ringing Doorbell
to GSI.  If suspend interrupt is received after this, it stops ringing
Doorbell to GSI and suspends path to GSI by calling xdci_suspend().

If suspend is received before enablement of data path as part of connect
handling, driver does enable GSI endpoints and starts ringing Doorbell to
GSI. This is not expected and resulting in USB controller accessing invalid
memory and causing SMMU fault. Fix it by bailing out data path enablement
if suspend event is pending.

Change-Id: I1603e4c675f85abff284c385c96230f1fb54231e
Signed-off-by: Vijayavardhan Vennapusa <vvreddy@codeaurora.org>