compat: backport phys_addr_t (CONFIG_PHYS_ADDR_T_64BIT)

compat: backport phys_addr_t (CONFIG_PHYS_ADDR_T_64BIT)

mcgrof@tux ~/linux-stable (git::linux-3.2.y)$ \
	git describe --contains 600715dcdf567c86f8b2c6173fcfb4b873e25a19
v2.6.28-rc1~271^2^4~6

The CONFIG_PHYS_ADDR_T_64BIT  was added as of v2.6.28-rc1~271^2^4~6,
this is either u32 or u64 dependent on 64BIT || ARCH_PHYS_ADDR_T_64BIT.
The ARCH_PHYS_ADDR_T_64BIT allows architectures to override the
value even if the platform does not have CONFIG_64BIT. We simplify
this check by just checking for all known architecture variables and
also the CONFIG_64BIT -- but we skip adding this if the arch is
x86 or PPC which already had phys_addr_t.

Signed-off-by: Luis R. Rodriguez <mcgrof@frijolero.org>