rename floatformat_ia64_quad_{big, little} to floatformat_ieee_quad_{big, little}

rename floatformat_ia64_quad_{big, little} to floatformat_ieee_quad_{big, little}

I submitted a GDB patch [1] to rename floatformats_ia64_quad to
floatformats_ieee_quad to reflect the reality, and then we can
clean up the related code.

As GDB Global Maintainer Tom Tromey said [2]:

  These files are maintained in gcc and then imported into the
  binutils-gdb repository, so any changes to them will have to
  be proposed there first.

this GCC patch is preparation for the GDB patch, no functionality
change.

[1] https://sourceware.org/pipermail/gdb-patches/2022-March/186452.html
[2] https://sourceware.org/pipermail/gdb-patches/2022-March/186569.html

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
include/
	* floatformat.h (floatformat_ieee_quad_big): Renamed from
	floatformat_ia64_quad_big.
	(floatformat_ieee_quad_little): Similarly.

libiberty/
	* floatformat.c (floatformat_ieee_quad_big): Renamed from
	floatformat_ia64_quad_big.
	(floatformat_ieee_quad_little): Similarly.