buildscript: buildall: call functions

Signed-off-by: Tim Niemeyer <tim@tn-x.org>
Reviewed-by: Jan Kraus <mayosemmel@gmail.com>

buildscript

@@ -341,9 +341,9 @@ setBSP()
 
 buildall() {
     for bsp in $(/bin/ls bsp/*.bsp); do
-        ./buildscript selectbsp "$bsp"
-        ./buildscript prepare
-        ./buildscript build "$1"
+        setBSP "$bsp"
+        prepare
+        build "$1"
     done
 }