linux: Update x86 vDSO symbols

Add the missing time and clock_getres vDSO symbol names on x86.
For time, the iFUNC already uses expected name so it affects only
the static build.

The clock_getres is a new implementation added on Linux 5.3
(f66501dc53e72).

Checked on x86-linux-gnu and i686-linux-gnu.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>