brcm80211: smac: rename buffer endianess conversion functions

The functions ltoh16_buf() and htol16_buf() have been renamed
to le16_to_cpu_buf() and cpu_to_le16_buf() for more clarity
what it does.

Reported-by: Joe Perches <joe@perches.com>
Reported-by: Larry Finger <Larry.Finger@lwfinger.net>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Alwin Beukers <alwin@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>