arm: mm: Use phys_addr_t properly for ioremap functions

Several of the ioremap functions use unsigned long in places
resulting in truncation if physical addresses greater than
4G are passed in. Change the types appropriately.

Change-Id: I1f8fb6999d6dbc4ca84c14c8163a72c1dc341143
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>