qemu: Remove deprecated asyncio calls in qmp python module

qemu: Remove deprecated asyncio calls in qmp python module

Fixes deprecation warning seen with python 3.13

DEBUG: QMP Initializing to /mnt/b/yoe/master/build/tmp/.sv4_k_q4

recipe-sysroot-native/usr/lib/qemu-python/qmp/legacy.py:89: DeprecationWarning: There is no current event loop
  self._aloop = asyncio.get_event_loop()

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>