slimbus: Add snapshot of slimbus driver.

This snapshot is taken as of msm-4.9 'commit <e8a6a75991d4>
("Merge "usb: core: Add usb_set_interface_timeout API"")'.

Change-Id: I8c4b1f9c7d2e288e82c086c64d1a07baf77c6015
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>