Joseph pointed out "floating types should have their mode,
not a poorly defined precision value" in the discussion[1],
as he and Richi suggested, the existing macros
{FLOAT,{,LONG_}DOUBLE}_TYPE_SIZE will be replaced with a
hook mode_for_floating_type.  To be prepared for that, this
patch is to remove the only one use of LONG_DOUBLE_TYPE_SIZE
in d.  Iain found that LONG_DOUBLE_TYPE_SIZE is poorly named
and used incorrectly before, so this patch follows his advice
with int_size_in_bytes.

[1] https://gcc.gnu.org/pipermail/gcc-patches/2024-May/651209.html



Co-authored-by: Iain Buclaw <ibuclaw@gdcproject.org>

gcc/d/ChangeLog:

	* d-target.cc (Target::_init): Use int_size_in_bytes of
	long_double_type_node to replace the expression with
	LONG_DOUBLE_TYPE_SIZE for c.long_doublesize assignment.