ARM: OMAP3: hwmod data: Remove legacy mailbox data and addrs

Remove the mailbox attribute data, irq info and hwmod addr space
data that are used for creating the legacy-style mailbox devices,
there is no need for these as the support for legacy-mode for this
IP is being dropped.

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