[rp2] Rename rp2040 platform to rp2 (#17145)

Co-authored-by: Jonathan Swoboda <154711427+swoboda1337@users.noreply.github.com>

tests/components/rp2/test.rp2040-ard.yaml

@@ -0,0 +1,17 @@
+rp2:
+  variant: rp2040
+  enable_full_printf: false
+
+logger:
+  level: VERBOSE
+
+esphome:
+  on_boot:
+    - lambda: |-
+        int x = 100;
+        x = clamp(x, 50, 90);
+        assert(x == 90);
+        x = clamp_at_least(x, 95);
+        assert(x == 95);
+        x = clamp_at_most(x, 40);
+        assert(x == 40);

tests/components/rp2/test.rp2350-ard.yaml

@@ -0,0 +1,6 @@
+rp2:
+  variant: rp2350
+  enable_full_printf: false
+
+logger:
+  level: VERBOSE