Simpler G28 home axis conditions

Marlin/src/gcode/calibrate/G28.cpp

@@ -260,13 +260,9 @@ void GcodeSuite::G28(const bool always_home_all) {
 
   #else // NOT DELTA
 
-    const bool homeX = always_home_all || parser.seen('X'),
+    const bool homeX = parser.seen('X'), homeY = parser.seen('Y'), homeZ = parser.seen('Z'),
-               homeY = always_home_all || parser.seen('Y'),
+               home_all = always_home_all || (homeX == homeY && homeX == homeZ),
-               homeZ = always_home_all || parser.seen('Z'),
+               doX = home_all || homeX, doY = home_all || homeY, doZ = home_all || homeZ;
-               home_all = (!homeX && !homeY && !homeZ) || (homeX && homeY && homeZ),
-               doX = home_all || homeX,
-               doY = home_all || homeY,
-               doZ = home_all || homeZ;
 
     set_destination_from_current();