fpga: spartan2: Fix printf arguments warning

That extra comma messes up format arguments.
Warning appears if built with FPGA_DEBUG defined:

      CC      drivers/fpga/spartan2.o
    /mnt/data/adahl/src/u-boot/drivers/fpga/spartan2.c: In function ‘spartan2_sp_load’:
    /mnt/data/adahl/src/u-boot/drivers/fpga/spartan2.c:112:11: warning: too many arguments for format [-Wformat-extra-args]
       PRINTF ("%s: Function Table:\n"
               ^~~~~~~~~~~~~~~~~~~~~~~
    /mnt/data/adahl/src/u-boot/drivers/fpga/spartan2.c:12:37: note: in definition of macro ‘PRINTF’
     #define PRINTF(fmt,args...) printf (fmt ,##args)
                                         ^~~
      CC      drivers/fpga/spartan3.o
    /mnt/data/adahl/src/u-boot/drivers/fpga/spartan3.c: In function ‘spartan3_sp_load’:
    /mnt/data/adahl/src/u-boot/drivers/fpga/spartan3.c:117:11: warning: too many arguments for format [-Wformat-extra-args]
       PRINTF ("%s: Function Table:\n"
               ^~~~~~~~~~~~~~~~~~~~~~~
    /mnt/data/adahl/src/u-boot/drivers/fpga/spartan3.c:17:37: note: in definition of macro ‘PRINTF’
     #define PRINTF(fmt,args...) printf (fmt ,##args)
                                         ^~~

Fixes: e2211743 ("Initial revision")
Signed-off-by: Alexander Dahl <ada@thorsis.com>
Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/20221007122003.11239-3-ada@thorsis.com