staging: r8188eu: fix a gcc warning

staging: r8188eu: fix a gcc warning

Replace strncpy with strlcpy to fix the following gcc warning.

drivers/staging/r8188eu/os_dep/ioctl_linux.c: In function 'rtw_wx_set_enc_ext':
drivers/staging/r8188eu/os_dep/ioctl_linux.c:1929:9: warning: 'strncpy' specified bound 16 equals destination size [-Wstringop-truncation]
 1929 |         strncpy((char *)param->u.crypt.alg, alg_name, IEEE_CRYPT_ALG_NAME_LEN);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The destination buffer size is IEEE_CRYPT_ALG_NAME_LEN and the length
of the string to copy is always < IEEE_CRYPT_ALG_NAME_LEN. So strlcpy
will never truncate the string.

Acked-by: Phillip Potter <phil@philpotter.co.uk>
Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20211018221231.7837-1-straube.linux@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>