staging: rtl8723bs: fix fortify warnings by using struct_group

staging: rtl8723bs: fix fortify warnings by using struct_group

Fix fortify_memcpy_chk warnings in rtw_BIP_verify() and
rtw_mgmt_xmitframe_coalesce() functions by using struct_group
to access consecutive address fields.

Changed memcpy calls to use &hdr->addrs instead of hdr->addr1
when copying 18 bytes (addr1 + addr2 + addr3).

This resolves 'detected read beyond size of field' warnings
by using the proper struct_group mechanism as suggested by
the compiler.

Signed-off-by: yingche <zxcv2569763104@gmail.com>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/20250829040906.895221-1-zxcv2569763104@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>