AVR/LibF7: target/122177 - fix fmin / fmax return value for one NaN arg.

AVR/LibF7: target/122177 - fix fmin / fmax return value for one NaN arg.

fmin and fmax should return the non-NaN argument in the case where
exactly one argument is a NaN.

Moreover, IEEE double fmin and fmax can be performed without
first converting the args to the internal representation and
then converting back again.

	PR target/122177
libgcc/config/avr/libf7/
	* libf7-common.mk (m_ddd): Remove: fmin, fmax.
	(F7_ASM_PARTS): Add: D_fminfmax.
	* libf7-asm.sx (D_fmanfmax): New module.
	* f7-wraps.h: Rebuild.

gcc/testsuite/
	* gcc.target/avr/fminfmax-1.c: New test.