libxml: disable lzma

libxml: disable lzma

On my system libxml-native got linked with host copy of liblzma and as a
result libxslt-native was not linkable:

| x86_64-linux-libtool: link: gcc -isystem/home/hrw/HDD/devel/canonical/ci-linaro/oecore/build/tmp-eglibc/sysroots/x86_64-linux/usr/include -O2 -pipe -Wall -Wl,-rpath-link -Wl,/home/hrw
/HDD/devel/canonical/ci-linaro/oecore/build/tmp-eglibc/sysroots/x86_64-linux/usr/lib -Wl,-rpath-link -Wl,/home/hrw/HDD/devel/canonical/ci-linaro/oecore/build/tmp-eglibc/sysroots/x86_64-
linux/lib -Wl,-rpath -Wl,/home/hrw/HDD/devel/canonical/ci-linaro/oecore/build/tmp-eglibc/sysroots/x86_64-linux/usr/lib -Wl,-rpath -Wl,/home/hrw/HDD/devel/canonical/ci-linaro/oecore/buil
d/tmp-eglibc/sysroots/x86_64-linux/lib -Wl,-O1 -o .libs/xsltproc xsltproc.o  -L/home/hrw/HDD/devel/canonical/ci-linaro/oecore/build/tmp-eglibc/sysroots/x86_64-linux/usr/lib -L/home/hrw/
HDD/devel/canonical/ci-linaro/oecore/build/tmp-eglibc/sysroots/x86_64-linux/lib ../libxslt/.libs/libxslt.so ../libexslt/.libs/libexslt.so /home/hrw/HDD/devel/canonical/ci-linaro/oecore/
build/tmp-eglibc/work/x86_64-linux/libxslt-native-1.1.26-r8/libxslt-1.1.26/libxslt/.libs/libxslt.so /home/hrw/HDD/devel/canonical/ci-linaro/oecore/build/tmp-eglibc/sysroots/x86_64-linux
/usr/lib/libxml2.so -ldl /home/hrw/HDD/devel/canonical/ci-linaro/oecore/build/tmp-eglibc/sysroots/x86_64-linux/usr/lib/liblzma.so -lrt -lz -lm -pthread -Wl,-rpath -Wl,/home/hrw/HDD/deve
l/canonical/ci-linaro/oecore/build/tmp-eglibc/sysroots/x86_64-linux/usr/lib
| /home/hrw/HDD/devel/canonical/ci-linaro/oecore/build/tmp-eglibc/sysroots/x86_64-linux/usr/lib/libxml2.so: undefined reference to `lzma_code@XZ_5.0'
| /home/hrw/HDD/devel/canonical/ci-linaro/oecore/build/tmp-eglibc/sysroots/x86_64-linux/usr/lib/libxml2.so: undefined reference to `lzma_auto_decoder@XZ_5.0'
| /home/hrw/HDD/devel/canonical/ci-linaro/oecore/build/tmp-eglibc/sysroots/x86_64-linux/usr/lib/libxml2.so: undefined reference to `lzma_end@XZ_5.0'
| /home/hrw/HDD/devel/canonical/ci-linaro/oecore/build/tmp-eglibc/sysroots/x86_64-linux/usr/lib/libxml2.so: undefined reference to `lzma_properties_decode@XZ_5.0'
| collect2: error: ld returned 1 exit status
| make[2]: *** [xsltproc] Error 1
| make[2]: Leaving directory `/home/hrw/HDD/devel/canonical/ci-linaro/oecore/build/tmp-eglibc/work/x86_64-linux/libxslt-native-1.1.26-r8/libxslt-1.1.26/xsltproc'

(From OE-Core rev: d4651d420a8cf359436a9614fbc9b56f901410c7)

Signed-off-by: Marcin Juszkiewicz <marcin.juszkiewicz@linaro.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>