ARM: shmobile: Use shmobile_init_late() on r8a7791 DT-only

Tie in shmobile_init_late for the DT-only r8a7791 SoC
Multiplatform support code. This will make sure that
Suspend-to-RAM, CPUIdle and CPUFreq get initialized.

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