ntp: drop uselss patch fixup which sometimes breaks rebuild

Drop sed line which no longer changes anything as upstream has changed to
use strrchr.  Worse, it bumps each ntpd/*.c file's modification time, which
sometimes triggers a strange dependency path causing the makefile to attempt
to run the ntpd keyword-gen app, which fails, because it's been
cross-compiled.

Signed-off-by: Danomi Manchego <danomimanchego123@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>