ksmbd: fix missing use of get_write in in smb2_set_ea()

Fix an issue where get_write is not used in smb2_set_ea().

Fixes: 6fc0a265 ("ksmbd: fix potential circular locking issue in smb2_set_ea()")
Cc: stable@vger.kernel.org
Reported-by: Wang Zhaolong <wangzhaolong1@huawei.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>