net: ipa: use upper_32_bits()

Use upper_32_bits() to extract the high-order 32 bits of a DMA
address.  This avoids doing a 32-position shift on a DMA address
if it happens not to be 64 bits wide.  Use lower_32_bits() to
extract the low-order 32 bits (because that's what it's for).

Suggested-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>