initramfs-framework-ima: UNPACKDIR fix

New poky uses UNPACKDIR instead of WORKDIR

Signed-off-by: Mikko Rapeli <mikko.rapeli@linaro.org>
Signed-off-by: Armin Kuster <akuster808@gmail.com>

meta-integrity/recipes-core/initrdscripts/initramfs-framework-ima.bb

@@ -25,7 +25,7 @@ REQUIRED_DISTRO_FEATURES = "ima"
 do_install () {
     install -d ${D}/${sysconfdir}/ima
     install -d ${D}/init.d
-    install ${WORKDIR}/ima  ${D}/init.d/20-ima
+    install ${UNPACKDIR}/ima  ${D}/init.d/20-ima
 
     sed -i "s/@@FORCE_IMA@@/${IMA_FORCE}/g" ${D}/init.d/20-ima
 }