eal/arm: fix build with gcc optimization level 0

eal/arm: fix build with gcc optimization level 0

GCC build with '-O0' on platforms with RTE_ARM_FEATURE_ATOMICS set
failed for:
 ../lib/librte_efd/rte_efd.c
 Assembler messages:
3866: Error: selected processor does not support `crc32cb w0,w0,w1'
3890: Error: selected processor does not support `crc32ch w0,w0,w1'
3914: Error: selected processor does not support `crc32cw w0,w0,w1'
3938: Error: selected processor does not support `crc32cx w0,w0,x1'

This was caused by an architecture specifier added for Clang.
Unlike Clang, GCC considers each inline assembly block to be dependent
and therefore, the architecture specifier impacts assemble of some
blocks require certain extension support.

Removed the architecture for GCC to fix the issue.

Fixes: 8fce34cd0a6a ("eal/arm: fix clang build of native target")
Cc: stable@dpdk.org
Reported-by: Feifei Wang <feifei.wang2@arm.com>
Signed-off-by: Ruifeng Wang <ruifeng.wang@arm.com>
Acked-by: Jerin Jacob <jerinj@marvell.com>