acl: fix build with some arm64 compiler

acl: fix build with some arm64 compiler

Some compilers reporting the following error, though the existing
code doesn't have any uninitialized variable case.
Just to make compiler happy, initialize the int32x4_t variable
one shot using vdupq_n_s32.

lib/librte_acl/acl_run_neon.h: In function 'search_neon_4'
lib/librte_acl/acl_run_neon.h:230:12: error:
  'input' may be used uninitialized in this function
  int32x4_t input;

Fixes: 34fa6c27c156 ("acl: add NEON optimization for ARMv8")
Cc: stable@dpdk.org
Suggested-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Signed-off-by: Jerin Jacob <jerinj@marvell.com>
Acked-by: Aaron Conole <aconole@redhat.com>