eal: add and use unaligned integer types

eal: add and use unaligned integer types

On machines that are strict on pointer alignment, current code breaks
on GCC's -Wcast-align checks on casts from narrower to wider types.
This patch introduces new unaligned_uint(16|32|64)_t types, which
correctly retain alignment in such cases.  Strict alignment
architectures will need to define CONFIG_RTE_ARCH_STRICT_ALIGN in
order to effect these new types.

Signed-off-by: Cyril Chemparathy <cchemparathy@ezchip.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>