ARM: OMAP4: hwmod_data: Remove legacy mailbox addrs

The legacy-style definition of the hwmod addr space is no longer
required after the addition of the OMAP4 mailbox DT node, so
clean up this data.

Cc: Paul Walmsley <paul@pwsan.com>
Cc: Benoît Cousson <bcousson@baylibre.com>
Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>