regulator: core: Limit regulators coupling to a single couple

Device tree binding was changed in a way that now max-spread values must
be defied per regulator pair. Limit number of pairs in order to adapt to
the new binding without changing regulators code.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

include/linux/regulator/driver.h

@@ -15,7 +15,7 @@
 #ifndef __LINUX_REGULATOR_DRIVER_H_
 #define __LINUX_REGULATOR_DRIVER_H_
 
-#define MAX_COUPLED		4
+#define MAX_COUPLED		2
 
 #include <linux/device.h>
 #include <linux/notifier.h>