staging: rtl8723bs: put parentheses on macros with complex values in include/hal_data.h

fix the following checkpatch warning:

ERROR: Macros with complex values should be enclosed in parentheses
49: FILE: drivers/staging/rtl8723bs/include/hal_data.h:49:
+#define CHANNEL_MAX_NUMBER
               14+24+21        /*  14 is the max channel number */

Signed-off-by: Fabio Aiuto <fabioaiuto83@gmail.com>
Link: https://lore.kernel.org/r/22c4bc695d3600fcaec18949c7521fa38aa4f4a0.1616854134.git.fabioaiuto83@gmail.com


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