staging: r8188eu: Remove unused static inline functions in rtw_recv.h

staging: r8188eu: Remove unused static inline functions in rtw_recv.h

After commit 987219ad34a6 ("staging: r8188eu: remove lines from Makefile
that silence build warnings"), clang warns several times:

In file included from
drivers/staging/r8188eu/os_dep/../include/drv_types.h:22:
drivers/staging/r8188eu/os_dep/../include/rtw_recv.h:395:9: warning:
variable 'buf_desc' is uninitialized when used here [-Wuninitialized]
        return buf_desc;
               ^~~~~~~~
drivers/staging/r8188eu/os_dep/../include/rtw_recv.h:391:25: note:
initialize the variable 'buf_desc' to silence this warning
        unsigned char *buf_desc;
                               ^
                                = NULL
drivers/staging/r8188eu/os_dep/../include/rtw_recv.h:412:52: warning:
variable 'buf_star' is uninitialized when used here [-Wuninitialized]
        precv_frame = rxmem_to_recvframe((unsigned char *)buf_star);
                                                          ^~~~~~~~
drivers/staging/r8188eu/os_dep/../include/rtw_recv.h:410:14: note:
initialize the variable 'buf_star' to silence this warning
        u8 *buf_star;
                    ^
                     = NULL
2 warnings generated.

The functions that these warnings come from are not used or are called
from functions that are not used so just remove them to remove the
warnings.

Acked-by: Phillip Potter <phil@philpotter.co.uk>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20210812204027.338872-2-nathan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>