!104 arm64 config: turn on Amazon ENA ethernet driver

Merge Pull Request from: @gjiang 
 
AWS arm64 instance needs the driver. Pls consider merge it for the three branches (OLK-5.10, openEuler-22.03-LTS and openEuler-22.09), thanks. 
 
Link:https://gitee.com/openeuler/kernel/pulls/104 
Reviewed-by: Zheng Zengkai <zhengzengkai@huawei.com> 
Reviewed-by: Liu Chao <liuchao173@huawei.com> 
Reviewed-by: Kai Liu <kai.liu@suse.com> 
Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com> 

arch/arm64/configs/openeuler_defconfig

@@ -2655,7 +2655,7 @@ CONFIG_NET_VENDOR_ALACRITECH=y
 # CONFIG_NET_VENDOR_ALTEON is not set
 # CONFIG_ALTERA_TSE is not set
 CONFIG_NET_VENDOR_AMAZON=y
-# CONFIG_ENA_ETHERNET is not set
+CONFIG_ENA_ETHERNET=m
 CONFIG_NET_VENDOR_AMD=y
 # CONFIG_AMD8111_ETH is not set
 # CONFIG_PCNET32 is not set