ARM: LPAE: use phys_addr_t in switch_mm()

This patch modifies the switch_mm() processor functions to use phys_addr_t.
On LPAE systems, we now honor the upper 32-bits of the physical address that
is being passed in, and program these into TTBR as expected.

Signed-off-by: Cyril Chemparathy <cyril@ti.com>
Signed-off-by: Vitaly Andrianov <vitalya@ti.com>
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Subash Patel <subash.rp@samsung.com>
[will: fixed up conflict in 3-level switch_mm with big-endian changes]
Signed-off-by: Will Deacon <will.deacon@arm.com>