libgcc: Fix a bug in _BitInt -> dfp conversions

The ia32 _BitInt support revealed a bug in floatbitint?d.c.
As can be even guessed from how the code is written in the loop,
the intention was to set inexact to non-zero whenever the remainder
after division wasn't zero, but I've ended up just checking whether
the 2 least significant limbs of the remainder were non-zero.
Now, in the dfp/bitint-4.c test in one case the remainder happens
to have least significant 64 bits zero and then the higher limbs are
non-zero; with 32-bit limbs that means 2 least significant limbs are zero
and so the code acted as if it was exactly divisible.

Fixed thusly.

2024-02-10  Jakub Jelinek  <jakub@redhat.com>

	* soft-fp/floatbitintdd.c (__bid_floatbitintdd): Or in all remainder
	limbs into inexact rather than just first two.
	* soft-fp/floatbitintsd.c (__bid_floatbitintsd): Likewise.
	* soft-fp/floatbitinttd.c (__bid_floatbitinttd): Likewise.