ARM: OMAP2+: Fix section warning for omap_init_ocp2scp()

Otherwise we will get:

WARNING: vmlinux.o(.text+0x1d4f0): Section mismatch in reference from the
function omap_init_ocp2scp() to the function .init.text:omap_device_build()
The function omap_init_ocp2scp() references
the function __init omap_device_build().
This is often because omap_init_ocp2scp lacks a __init
annotation or the annotation of omap_device_build is wrong.

Signed-off-by: Tony Lindgren <tony@atomide.com>