ARM: AM33xx: hwmod_data: Remove legacy mailbox addrs

The legacy-style definition of the hwmod addr space is no longer
required as AM33xx/AM43xx are DT-boot only, and the minimal mailbox
DT nodes have been added, so clean up this data.

Acked-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>