remove asm.S and neon.S from _SOURCES

This results in asm.S and neon.S getting assembled into object files and linked.
While for asm.S, this doesn't cause any problems, neon.S never ends up including
a .note.GNU-stack section resulting in the final library being marked as
requiring executable stack.

These files just define macros used by cpudetect.S and hevcdsp_qpel_neon.S so
them getting assembled and linked individually doesn't seem intended.

Author: oreo639

libde265/arm/Makefile.am

@@ -26,10 +26,10 @@ if ENABLE_ARM_THUMB
 endif
 
 libde265_arm_neon_la_SOURCES = \
-	asm.S \
 	cpudetect.S \
-	hevcdsp_qpel_neon.S \
-	neon.S
+	hevcdsp_qpel_neon.S
+
+EXTRA_DIST = asm.S neon.S
 
 if HAVE_VISIBILITY
 	libde265_arm_neon_la_CXXFLAGS += -DHAVE_VISIBILITY