bootanim: Use a for loop to make part# folders

Change-Id: Iec90f3521e589de4e8352c0349e1a0751d65d989

bootanimation/generate-bootanimation.sh

@@ -19,9 +19,10 @@ fi
 
 RESOLUTION=""$IMAGESIZE"x"$IMAGESIZE""
 
-mkdir -p $ANDROID_PRODUCT_OUT/obj/BOOTANIMATION/bootanimation/part0
-mkdir -p $ANDROID_PRODUCT_OUT/obj/BOOTANIMATION/bootanimation/part1
-mkdir -p $ANDROID_PRODUCT_OUT/obj/BOOTANIMATION/bootanimation/part2
+for part_cnt in 0 1 2
+do
+    mkdir -p $ANDROID_PRODUCT_OUT/obj/BOOTANIMATION/bootanimation/part$part_cnt
+done
 tar xfp "vendor/cm/bootanimation/bootanimation.tar" --to-command="convert - -resize '$RESOLUTION' \"png8:$OUT/bootanimation/\$TAR_FILENAME\""
 
 # Create desc.txt