dm: cpu: Fix undefined ENOSYS build error

Include <errno.h> otherwise ENOSYS is undefined.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>

common/cmd_cpu.c

@@ -9,6 +9,7 @@
 #include <command.h>
 #include <cpu.h>
 #include <dm.h>
+#include <errno.h>
 
 static const char *cpu_feature_name[CPU_FEAT_COUNT] = {
 	"L1 cache",

drivers/cpu/cpu-uclass.c

@@ -8,6 +8,7 @@
 #include <common.h>
 #include <cpu.h>
 #include <dm.h>
+#include <errno.h>
 #include <dm/lists.h>
 #include <dm/root.h>