ARM: bcm: mark bcm_kona_smc_init as __init

The bcm_kona_smc_init function references the bcm_kona_smc_ids variable
that is marked __initconst, so the function itself has to be __init
to avoid this build error:

WARNING: arch/arm/mach-bcm/built-in.o(.text+0x12c): Section mismatch in reference from the function bcm_kona_smc_init() to the (unknown reference) .init.rodata:(unknown)

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Christian Daudt <csd@broadcom.com>