fix: corrects order of e-charts dimensions

[pedrolamas]

Corrects the order or e-charts dimensions.

Tested with sample config:

[bed_mesh]
speed = 400
mesh_min = 5,5
mesh_max = 225,182
probe_count = 5, 4

[bed_mesh default]
version = 1
points = 
  -0.016250, -0.010833, 0.001667, 0.004167, 0.047500
  0.035000, 0.023750, 0.018750, -0.015000, 0.046667
  0.020417, 0.002083, 0.027500, 0.007500, 0.039167
  -0.000833, -0.030000, -0.028333, -0.019583, 0.008333
tension = 0.2
min_x = 5.0
algo = lagrange
y_count = 4
mesh_y_pps = 2
min_y = 5.0
x_count = 5
max_y = 182.0
mesh_x_pps = 2
max_x = 225.0

Results:

Introduced by fb9a46c

Fixes #1234