sh: Obliterate the P1 area macros

Replace the use of PHYSADDR() with __pa(). PHYSADDR() is based on the
idea that all addresses in P1SEG are untranslated, so we can access an
address's physical page as an offset from P1SEG. This doesn't work for
CONFIG_PMB/CONFIG_PMB_FIXED because pages in P1SEG and P2SEG are used
for PMB mappings and so can be translated to any physical address.

Likewise, replace a P1SEGADDR() use with virt_to_phys().

Signed-off-by: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>