Fixes Thumb2 related build failure

Patch below comes from the Debian libmad package.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

From: Konstantinos Margaritis <markos@debian.org>
Subject: use "adr" instead of "add" to make code ready for thumb2

--- ./imdct_l_arm.S.orig	2010-02-25 13:25:23.000000000 +0100
+++ ./imdct_l_arm.S	2010-02-25 13:27:26.000000000 +0100
@@ -468,7 +468,7 @@
 
     @----
 
-    add     r2, pc, #(imdct36_long_karray-.-8)  @ r2 = base address of Knn array (PIC safe ?)
+    adr     r2, imdct36_long_karray
 
 
 loop: