nvptx/mkoffload.cc: Fix "$nohost" check

If lhd_set_decl_assembler_name is invoked - in particular if
!TREE_PUBLIC (decl) && !DECL_FILE_SCOPE_P (decl) - the '.nohost' suffix
might change to '.nohost.2'. This happens for the existing reverse offload
testcases via cgraph_node::analyze and is a side effect of
r13-3455-g178ac530fe67e4f2fc439cc4ce89bc19d571ca31 for some reason.

The solution is to not only check for a tailing '$nohost' but also for
'$nohost$' in nvptx/mkoffload.cc.

gcc/ChangeLog:

	* config/nvptx/mkoffload.cc (process): Recognize '$nohost$...'
	besides tailing '$nohost' as being for reverse offload.