CRIS: Don't include tree.h in cris-protos.h, PR bootstrap/111021

While there's another patch that fixes the immediate error
in the PR by other means, the include of tree.h here is
something I prefer to avoid.

	PR bootstrap/111021
	* config/cris/cris-protos.h: Revert recent change.
	* config/cris/cris.cc (cris_legitimate_address_p): Remove
	code_helper unused parameter.
	(cris_legitimate_address_p_hook): New wrapper function.
	(TARGET_LEGITIMATE_ADDRESS_P): Change to
	cris_legitimate_address_p_hook.