qemu.inc: remove apm as a MACHINE_FEATURE

APM is not only obsolete, but requires a kernel config enabled and is meaningless for QEMU VM

[YOCTO #5121]

Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>