usb: msm72k_otg: Allow USB bus overdraw for Legacy OTG

This commit allow to set a new option in kernel config:
USB_MSM_OTG_72K_ALLOW_BUS_OVERDRAW

The option allows USB bus overdraw when using peripherals
attached via OTG on Legacy Qualcomm on-chip USB controller

Change-Id: I73544b7999a5beb02946e0ca9231fa2838625b29