elf: Fix tst-origin make rules

elf: Fix tst-origin make rules

The tst-origin build can fail with:

  /usr/bin/ld: [...]libc.so: undefined reference to `__tunable_is_initialized@GLIBC_PRIVATE'

Since the custom link invocation links against system glibc instead
of the built one.

The only requirement is to avoid liborigin.so linked with a full path,
which is the default for --enable-hardcoded-path-in-tests.  There
is no need to use a custom rule.

Checked on x86_64-linux-gnu.