V3.1.4 Support grove ultrasonic(use D8 port)

Author: UF

.travis.yml

@@ -131,7 +131,7 @@
 //#define SWIFT_TEST_MODE
 
 #define HW_VER  	"3.3"
-#define SW_VER_BASE  "3.1.3"
+#define SW_VER_BASE  "3.1.4"
 
 #ifdef SWIFT_TEST_MODE
 #define SW_VER  SW_VER_BASE"_t"

Marlin/Configuration.h

@@ -1818,7 +1818,7 @@ unsigned char inverse_kinematics(const float in_cartesian[3], float angle[3]) {
 
 	if (x < 0.1)
 	{
-		return -1;
+		x = 0.1;
 	}
 
 	// Calculate value of theta 1: the rotation angle