staging: r819xU_cmdpkt: Remove functionless method 'cmpk_handle_query_config_rx'

staging: r819xU_cmdpkt: Remove functionless method 'cmpk_handle_query_config_rx'

Fixes the following W=1 kernel build warning(s):

 drivers/staging/rtl8192u/r819xU_cmdpkt.c: In function ‘cmpk_handle_query_config_rx’:
 drivers/staging/rtl8192u/r819xU_cmdpkt.c:274:24: warning: variable ‘rx_query_cfg’ set but not used [-Wunused-but-set-variable]

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Michael Straube <straube.linux@gmail.com>
Cc: linux-staging@lists.linux.dev
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210414181129.1628598-7-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>