Remove the cpu_get_real_ticks() definition from linux-user/main.c.
This has been disabled via #if 0 and unused since commit 1dce7c3c22
in 2006; the definitions we actually use are in qemu-timer.h.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>