ARM: shmobile: Move EMEV2 CPU boot vector setup code

Move the boot vector setup code for the EMEV2 SoC to match
the sh73a0 and r8a7779 implementations. With this in place
all SoC specific SMP implementations for mach-shmobile uses
the ->smp_prepare_cpus() callback to setup the boot vector.

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>