src/codec: Fix typo in Makefile

Thanks to horizon for pointing this out

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/src/codec/Makefile.am b/src/codec/Makefile.am
index 5a54c42..d36e23f 100644
--- a/src/codec/Makefile.am
+++ b/src/codec/Makefile.am
@@ -8,4 +8,4 @@
 lib_LTLIBRARIES = libosmocodec.la
 
 libosmocodec_la_SOURCES = gsm610.c gsm620.c gsm660.c gsm690.c
-libosmocodec_la_LDFALGS = -version-info $(LIBVERSION)
+libosmocodec_la_LDFLAGS = -version-info $(LIBVERSION)