package/lttng-tools: fix typo in variable name

It's lttng-tools, not lttng-libust. ;-)

Fixes numerous build failures caused by a late autoreconf:
    http://autobuild.buildroot.org/results/b84/b84a6e39fcca70c56bfe49d54c385dfe6da82422/
    etc...

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/lttng-tools/lttng-tools.mk

@@ -11,7 +11,7 @@ LTTNG_TOOLS_LICENSE = GPL-2.0+, LGPL-2.1+ (include/lttng/*, src/lib/lttng-ctl/*)
 LTTNG_TOOLS_LICENSE_FILES = gpl-2.0.txt lgpl-2.1.txt LICENSE
 LTTNG_TOOLS_CONF_OPTS += --disable-man-pages
 # 0001-Fix-detect-dlmopen-and-disable-corresponding-tests-i.patch
-LTTNG_LIBUST_AUTORECONF = YES
+LTTNG_TOOLS_AUTORECONF = YES
 LTTNG_TOOLS_DEPENDENCIES = liburcu libxml2 popt util-linux
 
 ifeq ($(BR2_PACKAGE_LTTNG_LIBUST),y)