zephyr: make common.h compatible with Zephyr
Zephyr provides definitions for these macros.  Guard them away in the
preprocessor so we don't get warnings about duplicate definitions.
BRANCH=none
TEST=no warnings in follow-up CLs
#ifdef CONFIG_ZEPHYR
#include <sys/util.h>
+#include <toolchain.h>
#endif
/*
* Compared to directly using the preprocessor # operator, this 2-stage macro
* is safe with regards to using nested macros and defined arguments.
*/
+#ifndef CONFIG_ZEPHYR
#define STRINGIFY0(name) #name
#define STRINGIFY(name) STRINGIFY0(name)
+#endif /* CONFIG_ZEPHYR */
/* Macros to access registers */
#define REG64_ADDR(addr) ((volatile uint64_t *)(addr))
