rockchip: Add MIN() and MAX() macros back to M0 code

These macros were accidentally deleted in a previous cleanup. This
slipped through because the code using them is currently unused, but
that may change in the future.

Signed-off-by: Julius Werner <jwerner@chromium.org>

plat/rockchip/rk3399/drivers/m0/include/rk3399_mcu.h

@@ -46,6 +46,9 @@ typedef unsigned int uint32_t;
 #define mmio_clrsetbits_32(addr, clear, set) \
 		mmio_write_32(addr, (mmio_read_32(addr) & ~(clear)) | (set))
 
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+
 void handle_suspend(void);
 void handle_dram(void);
 void stopwatch_init_usecs_expire(unsigned int usecs);