staging: pi433: Remove the unused FREQUENCY define

FREQUENCY is not being used, delete its comment.
Signed-off-by: Shahar Avidar <ikobh7@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240227221204.534131-5-ikobh7@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/pi433/rf69.h

@@ -11,8 +11,6 @@
 #include "rf69_enum.h"
 #include "rf69_registers.h"
 
-/* NOTE: Modifying FREQUENCY value impacts CE certification */
-#define FREQUENCY	433920000	/* Hz */
 #define FIFO_SIZE	66		/* bytes */
 #define FIFO_THRESHOLD	15		/* bytes */