package/lcdproc: override freetype-config path

package/lcdproc: override freetype-config path

freetype-config from the host system may be used when installed.
Make sure that the one from STAGING_DIR is used.

checking if freetype support has been enabled... yes
checking for freetype-config... /usr/bin/freetype-config
checking for FreeType -- version >= 7.0.1... cross compiling; assuming OK... yes

Fixes:
http://autobuild.buildroot.net/results/c7c/c7c52cd56b985fd73434d5997e9a6ab3f7d7e71e

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>