input-selector: Fix waiting on EOS

input-selector: Fix waiting on EOS

This apparently got broken by bc1ec4e. Since self->blocked is always
FALSE, gst_input_selector_wait never actually waits.

Using (!self->eos || self->blocked) && ... as the loop condition would
be incorrect as well, because then the other call to the function in
_chain would block until EOS, so the functions cannot be merged trivially.

Since blocking is obsolete, gst_input_selector_wait will get removed anyway.
As such, just inline the loop.

https://bugzilla.gnome.org/show_bug.cgi?id=746518