c++: Fix thinko in auto return type checking [PR98441]

c++: Fix thinko in auto return type checking [PR98441]

This fixes a thinko in my r11-2085 patch: when I said "But only give the
!late_return_type errors when funcdecl_p, to accept e.g. auto (*fp)() = f;
in C++11" I should've done this, otherwise we give bogus errors mentioning
"function with trailing return type" when there is none.

gcc/cp/ChangeLog:

	PR c++/98441
	* decl.c (grokdeclarator): Move the !funcdecl_p check inside the
	!late_return_type block.

gcc/testsuite/ChangeLog:

	PR c++/98441
	* g++.dg/cpp0x/auto55.C: New test.