common: clean up setjmp.h

Separate setjmp.h into an architecture independent part and an architecture
specific part. This simplifies moving from using struct jmp_buf_data
directly to using type jmp_buf in our code which is the C compliant way.

Reviewed-by: Jerome Forissier <jerome.forissier@linaro.org>
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/arch/sandbox/cpu/cpu.c b/arch/sandbox/cpu/cpu.c
index 6407193..6db8739 100644
--- a/arch/sandbox/cpu/cpu.c
+++ b/arch/sandbox/cpu/cpu.c
@@ -10,10 +10,10 @@
 #include <errno.h>
 #include <log.h>
 #include <os.h>
+#include <setjmp.h>
 #include <asm/global_data.h>
 #include <asm/io.h>
 #include <asm/malloc.h>
-#include <asm/setjmp.h>
 #include <asm/state.h>
 #include <dm/ofnode.h>
 #include <linux/delay.h>