usb: common: Use a global definition for 'min3'

We can use a common global method for calculating minimum of
3 numbers. Put the same in 'common header' and let 'ehci'
use it.

Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
Acked-by: Tom Rini <trini@ti.com>
diff --git a/include/common.h b/include/common.h
index 8a1f3e4..40e4b07 100644
--- a/include/common.h
+++ b/include/common.h
@@ -199,18 +199,35 @@
  * General Purpose Utilities
  */
 #define min(X, Y)				\
-	({ typeof (X) __x = (X);		\
-		typeof (Y) __y = (Y);		\
+	({ typeof(X) __x = (X);			\
+		typeof(Y) __y = (Y);		\
 		(__x < __y) ? __x : __y; })
 
 #define max(X, Y)				\
-	({ typeof (X) __x = (X);		\
-		typeof (Y) __y = (Y);		\
+	({ typeof(X) __x = (X);			\
+		typeof(Y) __y = (Y);		\
 		(__x > __y) ? __x : __y; })
 
 #define MIN(x, y)  min(x, y)
 #define MAX(x, y)  max(x, y)
 
+#define min3(X, Y, Z)				\
+	({ typeof(X) __x = (X);			\
+		typeof(Y) __y = (Y);		\
+		typeof(Z) __z = (Z);		\
+		__x < __y ? (__x < __z ? __x : __z) :	\
+		(__y < __z ? __y : __z); })
+
+#define max3(X, Y, Z)				\
+	({ typeof(X) __x = (X);			\
+		typeof(Y) __y = (Y);		\
+		typeof(Z) __z = (Z);		\
+		__x > __y ? (__x > __z ? __x : __z) :	\
+		(__y > __z ? __y : __z); })
+
+#define MIN3(x, y, z)  min3(x, y, z)
+#define MAX3(x, y, z)  max3(x, y, z)
+
 /*
  * Return the absolute value of a number.
  *