staging: gs_fpgaboot: remove __TIMESTAMP__ macro

We specifically build the kernel with -Werror=date-time to detect
such macros, which gives us this error:

gs_fpgaboot/gs_fpgaboot.c:376:44: error: macro "__TIMESTAMP__" might prevent reproducible builds [-Werror=date-time]
  pr_info("built at %s UTC\n", __TIMESTAMP__);

The obvious fix is to remove the printk output line.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Insop Song <insop.song@gainspeed.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>