staging: pi433: Remove a duplicated FIFO_SIZE define

FIFO_SIZE is being used in both rf69.c & pi433_if.c source files.
It is also already defined in rf69.h header file.
Signed-off-by: Shahar Avidar <ikobh7@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240227221204.534131-2-ikobh7@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/pi433/rf69.c

@@ -13,7 +13,6 @@
 #include "rf69_registers.h"
 
 #define F_OSC	  32000000 /* in Hz */
-#define FIFO_SIZE 66	   /* in byte */
 
 /*-------------------------------------------------------------------------*/