usb: usb_bam: update endpoint index for SYS2BAM usecase

This change query IPA driver for SYS2BAM USB IPA endpoint
index and update the same to use with sps connect functionality.
It is required for RMNET and MBIM usecases.

Change-Id: I5e8dd6b1523b3617f581feff81da0c12c5877729
Signed-off-by: Mayank Rana <mrana@codeaurora.org>