staging: rtl8723bs: Replace custom RotR1 macro with ror16

The custom RotR1 macro reuses its argument, which throws a checkpatch
warning and can lead to unexpected side-effects if called with an
expression that has side-effects.

Remove the custom macro and replace its usages with the standard
kernel ror16() function from <linux/bitops.h> to clean up the code.

Signed-off-by: Patryk Gawroński <gawronski1.6@gmail.com>
Link: https://patch.msgid.link/20260722215327.62791-1-gawronski1.6@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>