janitor: move remaining public headers to include/

Headers in the root directory are now used only from within that
directory.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/config.h b/include/config.h
similarity index 100%
rename from config.h
rename to include/config.h

diff --git a/elf.h b/include/elf.h
similarity index 100%
rename from elf.h
rename to include/elf.h

diff --git a/libfdt_env.h b/include/libfdt_env.h
similarity index 100%
rename from libfdt_env.h
rename to include/libfdt_env.h

diff --git a/qemu-common.h b/include/qemu-common.h
similarity index 100%
rename from qemu-common.h
rename to include/qemu-common.h