device/device.h: Add `is_dev_enabled` function

There are many places where we do this. Put it inside an inline function
for convenience reasons.

Change-Id: I5515a52458b6c78c1a723cb08e6471eb9bac9cd6
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43871
Reviewed-by:  Felix Singer <felixsinger@posteo.net>
Reviewed-by: Michael Niewöhner
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/include/device/device.h b/src/include/device/device.h
index 082dcbb..3177854 100644
--- a/src/include/device/device.h
+++ b/src/include/device/device.h
@@ -195,6 +195,11 @@
 bool dev_is_active_bridge(struct device *dev);
 void add_more_links(struct device *dev, unsigned int total_links);
 
+static inline bool is_dev_enabled(const struct device *const dev)
+{
+	return dev && dev->enabled;
+}
+
 /* Option ROM helper functions */
 void run_bios(struct device *dev, unsigned long addr);