usb_bam: restructure and cleanup code to handle multi instances

Driver supports all the USB bam2bam connections that are
available for all USB cores -  DWC3, CI or HSIC. But, current
design requires single devicetree node to specify all the
information which affects readability and adds few DT attributes
with redundant information.
Cleanup all this mess by restructuring the driver to allow
each USB controller specify/register DT node corresponding to
its own BAM core only. Few DT related  modifications as part of
this patch include changing attribute e.g. bam_type, reset-on-connect
and reset-on-disconnect from per connection to per BAM instance,
and replacing src-bam-physical-address and dst-bam-physical-address
with peer-bam-physical-address as it is now straight forward to
pick USB BAM's physical address (src or dst depends on PIPE's DIR)
from the DT node's reg property.

Change-Id: I427f88c736fda3ae0a71f3641334cf4f2231756c
Signed-off-by: Manu Gautam <mgautam@codeaurora.org>