net: ipa: pass memory configuration data to ipa_mem_valid()

Pass the memory configuration data array to ipa_mem_valid() for
validation, and use that rather than assuming it's already been
recorded in the IPA structure.  Move the memory data array size
check into ipa_mem_valid().

Call ipa_mem_valid() early in ipa_mem_init(), and only proceed with
assigning the memory array pointer and size if it is found to be
valid.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>