[tca9548a] Allow separate I²C bus frequencies on each multiplexer port (#10422)

Co-authored-by: pre-commit-ci-lite[bot] <117423508+pre-commit-ci-lite[bot]@users.noreply.github.com>
Co-authored-by: J. Nick Koston <nick@koston.org>
Co-authored-by: J. Nick Koston <nick@home-assistant.io>

tests/components/tca9548a/common.yaml

@@ -2,9 +2,13 @@ tca9548a:
   - id: multiplex0
     i2c_id: i2c_bus
     address: 0x70
+    frequency: 400 kHz
     channels:
       - bus_id: multiplex0_chan0
         channel: 0
+      - bus_id: multiplex0_chan1
+        channel: 1
+        frequency: 1 MHz
   - id: multiplex1
     i2c_id: i2c_bus
     address: 0x71

tests/components/tca9548a/test.nrf52-adafruit.yaml

@@ -0,0 +1,3 @@
+packages:
+  i2c: !include ../../test_build_components/common/i2c/nrf52.yaml
+  tca9548a: !include common.yaml