Offset label changed to be more appropriate

The label "Offset" was for me not clear what this does.
For the Horus and X9 there is room for an "Idle offset" label which is perfectly clear.

I think, for the X7, "Idle" is the best option, also set x=58 so it lines up nicely.
Tested on my QX7S.

Author: 0crap

src/SCRIPTS/BF/X7/pwm.lua

@@ -12,7 +12,7 @@ return {
         { t = "Prot", x = 58, y = 14, to = SMLSIZE },
         { t = "Unsync", x = 58, y = 24, to = SMLSIZE },
         { t = "PWM", x = 58, y = 34, to = SMLSIZE },
-        { t = "Offset", x = 48, y = 44, to = SMLSIZE }
+        { t = "Idle", x = 58, y = 44, to = SMLSIZE }
     },
     fields = {
         { x = 32, y = 14, vals = { 9 }, min = 0, max = 1, to = SMLSIZE, table = { [0] = "OFF", "ON" }, upd = function(self) self.updateRateTables(self) end },