respect alignment in arm asm files

Conversion script was discarding alignment. Also, set default alignment
to 4 bytes.

Change-Id: I1e9cbbb8c142bdf93df4e9aaccf967ed43dff906
https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/789198
diff --git a/build/make/ads2gas.pl b/build/make/ads2gas.pl
index efdfce7..be46582 100755
--- a/build/make/ads2gas.pl
+++ b/build/make/ads2gas.pl
@@ -82,7 +82,10 @@
     s/CODE([0-9][0-9])/.code $1/;
 
     # No AREA required
-    s/^\s*AREA.*$/.text/;
+    # But ALIGNs in AREA must be obeyed
+    s/^\s*AREA.*ALIGN=([0-9])$/.text\n.p2align $1/;
+    # If no ALIGN, strip the AREA and align to 4 bytes
+    s/^\s*AREA.*$/.text\n.p2align 2/;
 
     # DCD to .word
     # This one is for incoming symbols