Revert "usb: gadget: f_gsi: Consolidate ep_intr_num programming"

This reverts 'commit 33d380ea ("usb: gadget: f_gsi: Consolidate
ep_intr_num programming")' which incorrectly assigned 2 as interrupter
number of ECM's IN EP when used with cv2x instead of using 3
which is freed from ADPL.

Change-Id: I9550de8bb3fa464313f9c0d6ad4ed94860691d38
Signed-off-by: Manu Gautam <mgautam@codeaurora.org>