[mqtt] Enable support for the RTL87XX platform (#7697)

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>
Co-authored-by: Jonathan Swoboda <154711427+swoboda1337@users.noreply.github.com>
Co-authored-by: pre-commit-ci-lite[bot] <117423508+pre-commit-ci-lite[bot]@users.noreply.github.com>

esphome/components/mqtt/__init__.py

@@ -55,6 +55,7 @@ from esphome.const import (
     PLATFORM_BK72XX,
     PLATFORM_ESP32,
     PLATFORM_ESP8266,
+    PLATFORM_RTL87XX,
     PlatformFramework,
 )
 from esphome.core import CORE, CoroPriority, coroutine_with_priority
@@ -316,7 +317,7 @@ CONFIG_SCHEMA = cv.All(
         }
     ),
     validate_config,
-    cv.only_on([PLATFORM_ESP32, PLATFORM_ESP8266, PLATFORM_BK72XX]),
+    cv.only_on([PLATFORM_ESP32, PLATFORM_ESP8266, PLATFORM_BK72XX, PLATFORM_RTL87XX]),
     _consume_mqtt_sockets,
 )
 

tests/components/mqtt/test.rtl87xx-ard.yaml

@@ -0,0 +1,2 @@
+packages:
+  common: !include common.yaml

tests/test_build_components/build_components_base.rtl87xx-ard.yaml

@@ -0,0 +1,15 @@
+esphome:
+  name: componenttestesprtl87xx
+  friendly_name: $component_name
+
+rtl87xx:
+  board: generic-rtl8710bn-2mb-788k
+
+logger:
+  level: VERY_VERBOSE
+
+packages:
+  component_under_test: !include
+    file: $component_test_file
+    vars:
+      component_test_file: $component_test_file