ARM: mach-shmobile: Fix build when SMP is enabled and EMEV2 is not enabled

Build failed, when SMP is enabled and EMEV2 is not enabled.

arch/arm/mach-shmobile/built-in.o: In function `shmobile_platform_cpu_kill':
/home/iwamatsu/work/kernel/sh-2.6-devel/arch/arm/mach-shmobile/platsmp.c:62: undefined reference to `emev2_platform_cpu_kill'
arch/arm/mach-shmobile/built-in.o: In function `shmobile_smp_get_core_count':
/home/iwamatsu/work/kernel/sh-2.6-devel/arch/arm/mach-shmobile/platsmp.c:39: undefined reference to `emev2_get_core_count'
arch/arm/mach-shmobile/built-in.o: In function `shmobile_smp_prepare_cpus':
/home/iwamatsu/work/kernel/sh-2.6-devel/arch/arm/mach-shmobile/platsmp.c:53: undefined reference to `emev2_smp_prepare_cpus'
arch/arm/mach-shmobile/built-in.o: In function `platform_secondary_init':
/home/iwamatsu/work/kernel/sh-2.6-devel/arch/arm/mach-shmobile/platsmp.c:78: undefined reference to `emev2_secondary_init'
arch/arm/mach-shmobile/built-in.o: In function `boot_secondary':
/home/iwamatsu/work/kernel/sh-2.6-devel/arch/arm/mach-shmobile/platsmp.c:90: undefined reference to `emev2_boot_secondary

This is the cause by when EMEV2 is disabled, that the check by OF of EMEV2 is
performed in platsmp.c.
This patch revise what the function about EMEV2 may not be used in this file,
when EMEV2 is not enabled.

Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Acked-by: Simon Horman <horms@verge.net.au>
Acked-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>