USB: u_bam: Check cable connect status after usb_bam_connect_ipa()

Currently driver is not checking cable connect status after calling
usb_bam_connect_ipa() to setup BAM2BAM connection with IPA. If there
is disconnect & connect during this time, it might crash later when
endless request is queued to USB controller.

Change-Id: I6b65d959596b57f7a59e1857c5239b6888c55619
Signed-off-by: Vijayavardhan Vennapusa <vvreddy@codeaurora.org>