ARM: OMAP4+: PRM: determine prm_device_inst based on DT compatibility

PRM device instance offset is now provided through the prm_init_data.
This gets rid of some cpu_is_X / soc_is_X calls from PRM core code,
preparing for PRM to be its own separate driver.

Signed-off-by: Tero Kristo <t-kristo@ti.com>

diff --cc arch/arm/mach-omap2/prcm-common.h
Simple merge

diff --cc arch/arm/mach-omap2/prm44xx.c
Simple merge

diff --cc arch/arm/mach-omap2/prm_common.c
Simple merge

diff --cc arch/arm/mach-omap2/prminst44xx.c
Simple merge

diff --cc arch/arm/mach-omap2/prminst44xx.h
Simple merge