staging: rtl8723bs: Remove unused function prototype ODM_SetAntenna()

Remove unused function prototype ODM_SetAntenna.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
Link: https://lore.kernel.org/r/20190725052645.2372-9-nishkadg.linux@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>