We currently assume the IPA driver is built only for a 64 bit kernel.

When this constraint was put in place it eliminated some do_div()
calls, replacing them with the "/" and "%" operators.  We now only
use these operations on u32 and size_t objects.  In a 32-bit kernel
build, size_t will be 32 bits wide, so there remains no reason to
use do_div() for divide and modulo.

A few recent commits also fix some code that assumes that DMA
addresses are 64 bits wide.

With that, we can get rid of the 64-bit build requirement.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>