ARM: OMAP2+: hwmod: extend OCP_* register offsets from 16 to 32 bits

Extend the OCP_* register offsets in the struct
omap_hwmod_class_sysconfig to 32 bits.  This is required to add the
OMAP4+ GPU hwmod, which uses OCP_* register offsets larger than 16
bits.

Another possible solution may be to simply add a single 16 bit offset
field in this structure, and to add code to factor that offset into
all OCP_* register accesses.  This would save some memory, since
almost no modules need 32 bit offsets.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Benoît Cousson <b-cousson@ti.com>