eal/arm: fix debug build with gcc for 128-bit atomics

eal/arm: fix debug build with gcc for 128-bit atomics

Compiling with "meson build -Dbuildtype=debug --cross-file
config/arm/arm64_thunderx2_linux_gcc" shows the warnings
"function returns an aggregate [-Waggregate-return]":
../../dpdk/lib/librte_eal/arm/include/rte_atomic_64.h: In
function ‘__cas_128_relaxed’:
../../dpdk/lib/librte_eal/arm/include/rte_atomic_64.h:81:20:
error: function returns an aggregate [-Werror=aggregate-return]
 __ATOMIC128_CAS_OP(__cas_128_relaxed, "casp")
                    ^~~~~~~~~~~~~~~~~

Fix the compiling issue by defining __ATOMIC128_CAS_OP as a void
function and passing the address pointer into it.

Fixes: 7e2c3e17fe2c ("eal/arm64: add 128-bit atomic compare exchange")
Cc: stable@dpdk.org
Signed-off-by: Joyce Kong <joyce.kong@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Acked-by: Jerin Jacob <jerinj@marvell.com>