mfd: altera-sysmgr: Fix physical address storing hacks

Sparse reports:

 drivers/mfd/altera-sysmgr.c:150:30: warning: incorrect type in assignment (different address spaces)
 drivers/mfd/altera-sysmgr.c:150:30:    expected unsigned int [usertype] *base
 drivers/mfd/altera-sysmgr.c:150:30:    got void [noderef] <asn:2> *
 drivers/mfd/altera-sysmgr.c:156:26: warning: incorrect type in argument 3 (different address spaces)
 drivers/mfd/altera-sysmgr.c:156:26:    expected void [noderef] <asn:2> *regs
 drivers/mfd/altera-sysmgr.c:156:26:    got unsigned int [usertype] *base

It appears as though the driver data property 'resource_size_t *base'
was being used to store 2 different types of addresses (physical and
IO-mapped) under a single declared type.

Fortunately, no value is recalled from the driver data entry, so it
can be easily omitted.  Instead we can use the value obtained directly
from the platform resource to pass through  Regmap into the call-backs
to be used for the SMCC call and use a local dedicated __iomem
variable for IO-remapping.

Cc: Thor Thayer <thor.thayer@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>