libgcc: Fix BIL_TYPE_SIZE == 32 support in _BitInt <-> dfp support

I've tried last night to enable _BitInt support for i?86-linux, and
a few spots in libgcc emitted -Wshift-count-overflow warnings and clearly
didn't do what it was supposed to do.

Fixed thusly.

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

	* soft-fp/fixddbitint.c (__bid_fixddbitint): Fix up
	BIL_TYPE_SIZE == 32 shifts.
	* soft-fp/fixsdbitint.c (__bid_fixsdbitint): Likewise.
	* soft-fp/fixtdbitint.c (__bid_fixtdbitint): Likewise.
	* soft-fp/floatbitintdd.c (__bid_floatbitintdd): Likewise.
	* soft-fp/floatbitinttd.c (__bid_floatbitinttd): Likewise.