iwlwifi: mvm: rfi: use kmemdup() to replace kzalloc + memcpy

Fix memdup.cocci warning:
./drivers/net/wireless/intel/iwlwifi/mvm/rfi.c:110:8-15: WARNING
opportunity for kmemdup

Signed-off-by: Bixuan Cui <cuibixuan@linux.alibaba.com>
Link: https://lore.kernel.org/r/1635317920-84725-1-git-send-email-cuibixuan@linux.alibaba.com


Signed-off-by: Luca Coelho <luciano.coelho@intel.com>