ARM: OMAP2+: Fix build with CONFIG_SMP and CONFIG_PM is not set

I found one more make randconfig build error with the recent
SMP kexec changes. We need the mpuss now always available early.

Fixes: 0573b957 ("ARM: OMAP4+: Prevent CPU1 related hang
with kexec")
Signed-off-by: Tony Lindgren <tony@atomide.com>