ARM: OMAP5: hwmod data: Add mailbox data

Add the hwmod data for the mailbox IP in OMAP5 SoC.
This is needed to be able to enable the OMAP mailbox
support for OMAP5.

Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>