ARM: OMAP3/4: omap_hwmod: Add rstst_offs field to struct omap_hwmod_omap4_prcm

ARM: OMAP3/4: omap_hwmod: Add rstst_offs field to struct omap_hwmod_omap4_prcm

In case of AM33XX device, XXX_RSTST register offset is not
consistent across PRM modules/instances,

PRM_XXX            RSTST
=========================
PRM_PER_MOD:       0x04
PRM_WKUP_MOD:      0x0C
PRM_MPU_MOD:       NA
PRM_DEVICE_MOD:    0x08

This means, we need to pass on XXX_RSTST register offset
information through omap_hwmod data, similar to XXX_RSTCTRL.

Currently, this field is only applicable and used for AM33XX
devices.

Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>