ARM: shmobile: Remove old SCU boot code

Remove shmobile_secondary_vector_scu now when all SCU enabled
SMP platforms instead make use of shmobile_boot_scu. This
removes two inline virtual to physical address conversions.

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