common/cnxk: add include for macro definition

common/cnxk: add include for macro definition

The header file "roc_io.h" uses the "__plt_always_inline" macro but
don't include "roc_platform.h" to get the definition of it. This
inclusion is not necessary for compilation, but the lack of it can
confuse some indexers - such as those in eclipse, which reports the
lines:

"static __plt_always_inline uint64_t"

as possible definitions of a variable called "uint64_t". This confusion
leads to uint64_t being flagged as an unknown type in all other parts of
the project being indexed, e.g. across all of DPDK code.

Adding in the include of roc_platform.h makes it clear to the indexer
that those lines are  part of a function definition, and that allows
eclipse to correctly recognise uint64_t as a type from stdint.h

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Jerin Jacob <jerinj@marvell.com>