staging: rtl8723bs: remove header file ethernet.h

staging: rtl8723bs: remove header file ethernet.h

The header file ehternet.h defines only two constants.

#define ETHERNET_HEADER_SIZE   14          /*  Ethernet Header Length */
#define LLC_HEADER_SIZE         6          /*  LLC Header Length */

Both are only used in the file core/rtw_recv.c and ETHERNET_HEADER_SIZE
just duplicates the in-kernel constant ETH_HLEN. Replace the usage of
ETHERNET_HEADER_SIZE with ETH_HLEN, move the definition of LLC_HEADER_SIZE
into rtw_rev.h (renamed to LLC_HEADER_LENGTH) and remove the now unused
header file ethernet.h.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20210825100842.13217-1-straube.linux@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>