Changed README.md with links added board folder in the paths

README.md

@@ -8,9 +8,9 @@ I tested follwing boards:
 | Board |  |
 | --- | --- | 
 | Up ² | [Up2](boards/up-squared.md) | 
-| Raspberry Pi 3 | [Pi 3](raspberry_pi3.md) | 
-| Raspberry Pi 4 | [Pi 4](raspberry_pi4.md) | 
-| Surface Pro 2 | [Surface Pro 2](surface_pro2.md) | 
+| Raspberry Pi 3 | [Pi 3](boards/raspberry_pi3.md) | 
+| Raspberry Pi 4 | [Pi 4](boards/raspberry_pi4.md) | 
+| Surface Pro 2 | [Surface Pro 2](boards/surface_pro2.md) | 
 
 
 The following list contains some information to getting started with some features: