gcc: xtensa: fix PR target/108919

gcc/
	PR target/108919

	* config/xtensa/xtensa-protos.h
	(xtensa_prepare_expand_call): Rename to xtensa_expand_call.
	* config/xtensa/xtensa.cc (xtensa_prepare_expand_call): Rename
	to xtensa_expand_call.
	(xtensa_expand_call): Emit the call and add a clobber expression
	for the static chain to it in case of windowed ABI.
	* config/xtensa/xtensa.md (call, call_value, sibcall)
	(sibcall_value): Call xtensa_expand_call and complete expansion
	right after that call.

gcc/testsuite/
	* gcc.target/xtensa/pr108919.c: New test.