After previous cleanups a lot of functions from qemu_hotplug.c
are called only within the file. Make them static and drop their
declaration from the header file.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
---
 src/qemu/qemu_hotplug.c | 56 +++++++++++++++++++++----------------
 src/qemu/qemu_hotplug.h | 61 -----------------------------------------
 2 files changed, 32 insertions(+), 85 deletions(-)