process.c: move getcpu parser to a separate file

* getcpu.c: New file.
* Makefile.am (strace_SOURCES): Add it.
* process.c (sys_getcpu): Move to getcpu.c.
diff --git a/Makefile.am b/Makefile.am
index b6503ed..cd097a4 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -33,6 +33,7 @@
 	fallocate.c	\
 	fanotify.c	\
 	file.c		\
+	getcpu.c	\
 	getcwd.c	\
 	inotify.c	\
 	io.c		\