gas: Explicitly code void parameter list

gas: Explicitly code void parameter list

This fixes the following compile errors reported by Clang:

  CC       config/obj-elf-attr.o
../../gas/config/obj-elf-attr.c:64:21: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
   64 | oav1_attr_info_init ()
      |                     ^
      |                      void
../../gas/config/obj-elf-attr.c:74:21: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
   74 | oav1_attr_info_exit ()
      |                     ^
      |                      void

gas/
	* config/obj-elf-attr.c (oav1_attr_info_init,
	oav1_attr_info_exit): Explicitly code void parameter list.

Signed-off-by: Jens Remus <jremus@linux.ibm.com>