envsetup: Update mka for O

Change-Id: I36ec10be9152f135ec3645b4304e63ea30d06774

build/envsetup.sh

@@ -672,20 +672,14 @@ function lineagerebase() {
 }
 
 function mka() {
-    local T=$(gettop)
-    if [ "$T" ]; then
     case `uname -s` in
         Darwin)
-                make -C $T -j `sysctl hw.ncpu|cut -d" " -f2` "$@"
+            m -j "$@"
             ;;
         *)
-                mk_timer schedtool -B -n 10 -e ionice -n 7 make -C $T -j$(grep "^processor" /proc/cpuinfo | wc -l) "$@"
+            mk_timer schedtool -B -n 10 -e ionice -n 7 m -j "$@"
             ;;
     esac
-
-    else
-        echo "Couldn't locate the top of the tree.  Try setting TOP."
-    fi
 }
 
 function cmka() {