Update RB750r2.yaml (#1066)

* Update RB750r2.yaml

* Update RB750r2.yaml

Added `airflow: passive`

* Update RB750r2.yaml

The specs on this are completely wrong for the power ports.
https://mikrotik.com/product/RB750r2

Fixed DC PSU to be dc-terminal with a max draw of 2W

* Update RB750r2.yaml

Added comment with product page URL

---------

Co-authored-by: Daniel W. Anner <daniel.anner@danstechsupport.com>

device-types/MikroTik/RB750r2.yaml

@@ -2,6 +2,10 @@
 manufacturer: MikroTik
 model: RB750r2
 slug: mikrotik-rb750r2
+airflow: passive
+is_full_depth: false
+u_height: 0
+comments: '[MikroTik RB750r2 Product Page](https://mikrotik.com/product/RB750r2)'
 interfaces:
   - name: ether1
     type: 100base-tx
@@ -14,9 +18,10 @@ interfaces:
   - name: ether5
     type: 100base-tx
 power-ports:
-  - name: DC
-    type: iec-60320-c14
-    maximum_draw: 350
+  - name: PSU1
+    type: dc-terminal
+    maximum_draw: 2
+    label: dc-power-in
 console-ports:
   - name: Console
     type: rj-45