irqdomain: Add a name field

This patch adds a name field to the irq_domain structure to help mere
mortals understand the mappings between irq domains and virqs. It also
converts a number of places that have open-coded some kind of fudging
an irqdomain name to use the new field. This means a more consistent
display of names in irq domain log messages and debugfs output.

Signed-off-by: Grant Likely <grant.likely@linaro.org>

include/linux/irqdomain.h

@@ -89,6 +89,7 @@ struct irq_domain_chip_generic;
  */
 struct irq_domain {
 	struct list_head link;
+	const char *name;
 
 	/* type of reverse mapping_technique */
 	unsigned int revmap_type;