qemu: rename deprecated --enable-trace-backend configure option

qemu 6.2 deprecated the configure option '--enable-trace-backend' in favor
of '--enable-trace-backends' [1]

Rename accordingly.

[1] https://wiki.qemu.org/ChangeLog/6.2#Build_Information

(From OE-Core rev: 9e41fac1c2ee15aaff9926dac3c0233430adff12)

Signed-off-by: Thomas De Schampheleire <thomas.de_schampheleire@nokia.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/qemu/qemu.inc

@@ -208,7 +208,7 @@ PACKAGECONFIG[libudev] = "--enable-libudev,--disable-libudev,eudev"
 PACKAGECONFIG[attr] = "--enable-attr,--disable-attr,attr,"
 PACKAGECONFIG[rbd] = "--enable-rbd,--disable-rbd,ceph,ceph"
 PACKAGECONFIG[vhost] = "--enable-vhost-net,--disable-vhost-net,,"
-PACKAGECONFIG[ust] = "--enable-trace-backend=ust,,lttng-ust,"
+PACKAGECONFIG[ust] = "--enable-trace-backends=ust,,lttng-ust,"
 PACKAGECONFIG[pie] = "--enable-pie,--disable-pie,,"
 PACKAGECONFIG[seccomp] = "--enable-seccomp,--disable-seccomp,libseccomp"
 # libnfs is currently provided by meta-kodi