fix: skip midi2_host_feather build on non-RP2040 platforms

The Makefile was missing the FAMILY=rp2040 guard, causing CI failures
on stm32h7rs and other non-RP2040 targets. Matches the approach used
by midi2_host.

Author: sauloverissimo

examples/host/midi2_host_feather/Makefile

@@ -1 +1,27 @@
-include ../../../examples/build_system/make/make.mk
+# This example requires RP2040 (PIO-USB, Pico SDK I2C, SSD1306 display)
+ifeq (,$(findstring rp2040,$(FAMILY)))
+$(info Skipping midi2_host_feather: requires FAMILY=rp2040)
+all:
+	@:
+.DEFAULT:
+	@:
+else
+
+include ../../../hw/bsp/family_support.mk
+
+INC += \
+	src \
+
+# Example source
+EXAMPLE_SOURCE += \
+  src/main.c \
+  src/display.c \
+
+SRC_C += $(addprefix $(EXAMPLE_PATH)/, $(EXAMPLE_SOURCE))
+
+# Suppress pre-existing warning
+CFLAGS_GCC += -Wno-type-limits
+
+include ../../../hw/bsp/family_rules.mk
+
+endif