or1k: move or1k_atomic parser to a separate file

* or1k_atomic.c: New file.
* Makefile.am (strace_SOURCES): Add it.
* system.c [OR1K]: Move to or1k_atomic.c.
diff --git a/Makefile.am b/Makefile.am
index f046e0c..38193f2 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -37,6 +37,7 @@
 	mem.c		\
 	mtd.c		\
 	net.c		\
+	or1k_atomic.c	\
 	pathtrace.c	\
 	process.c	\
 	ptp.c		\