ARM: omap1: enable multiplatform

With all the header files out of the way, and the clock driver
converted to the common framework, nothing stops us from building
OMAP together with the other platforms.

As usual, the decompressor support is a victim here, and is
only available when CONFIG_DEBUG_LL is configured for the
particular board.

Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>