SPC/Coldfire: Just use msac.w instead of neg.l/mac.w. It seems fine. Must've been cache aliasing. :-)

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@15532 a1c6a512-1295-4272-9138-f99709370657
diff --git a/apps/codecs/spc/spc_dsp.c b/apps/codecs/spc/spc_dsp.c
index 6a8aaeb..8881788 100644
--- a/apps/codecs/spc/spc_dsp.c
+++ b/apps/codecs/spc/spc_dsp.c
@@ -812,10 +812,8 @@
                 "move.l     2(%[s], %[y1].l*2), %[y1] \r\n"
                 /* %acc0 = f*y1                          */
                 "mac.w      %[f]l, %[y1]l, %%acc0     \r\n"
-                /* msac.w is 2% boostier so add negative */
-                "neg.l      %[f]                      \r\n"
                 /* %acc0 -= f*y0                         */
-                "mac.w      %[f]l, %[y1]u, %%acc0     \r\n"
+                "msac.w     %[f]l, %[y1]u, %%acc0     \r\n"
                 /* separate out y0 and sign extend       */
                 "swap       %[y1]                     \r\n"
                 "movea.w    %[y1], %[y0]              \r\n"