makes w_class use defines (#9848)

code/modules/power/smes_construction.dm

@@ -11,7 +11,7 @@
 	desc = "Standard superconductive magnetic coil with average capacity and I/O rating."
 	icon = 'icons/obj/stock_parts.dmi'
 	icon_state = "smes_coil"			// Just few icons patched together. If someone wants to make better icon, feel free to do so!
-	w_class = 4.0 						// It's LARGE (backpack size)
+	w_class = ITEMSIZE_LARGE 						// It's LARGE (backpack size)
 	var/ChargeCapacity = 5000000
 	var/IOCapacity = 250000
 

code/modules/power/solar.dm

@@ -204,7 +204,7 @@
 	icon = 'icons/obj/power.dmi'
 	icon_state = "sp_base"
 	item_state = "electropack"
-	w_class = 4 // Pretty big!
+	w_class = ITEMSIZE_LARGE // Pretty big!
 	anchored = 0
 	var/tracker = 0
 	var/glass_type = null

code/modules/power/tracker.dm

@@ -80,4 +80,4 @@
 	name = "tracker electronics"
 	icon = 'icons/obj/doors/door_assembly.dmi'
 	icon_state = "door_electronics"
-	w_class = 2.0
+	w_class = ITEMSIZE_SMALL