ARM: OMAP2+: hwmod: Add USB hwmod data for AM437x.

Add hwmod for USBSS and the OCP2SCP for AM437x.
AM437x has got 2 instances of USBSS.

Signed-off-by: George Cherian <george.cherian@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>