Documentation/IRQ-domain.txt: Document irq_domain_create_{linear, tree}

They have the same functionalities as irq_domain_add_{linear, tree},
except fro accepting different first argument.
Signed-off-by: Jianyu Zhan <nasa4836@gmail.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/IRQ-domain.txt

@@ -70,6 +70,7 @@ of the reverse map types are described below:
 
 ==== Linear ====
 irq_domain_add_linear()
+irq_domain_create_linear()
 
 The linear reverse map maintains a fixed size table indexed by the
 hwirq number.  When a hwirq is mapped, an irq_desc is allocated for
@@ -81,10 +82,16 @@ map are fixed time lookup for IRQ numbers, and irq_descs are only
 allocated for in-use IRQs.  The disadvantage is that the table must be
 as large as the largest possible hwirq number.
 
+irq_domain_add_linear() and irq_domain_create_linear() are functionally
+equivalent, except for the first argument is different - the former
+accepts an Open Firmware specific 'struct device_node', while the latter
+accepts a more general abstraction 'struct fwnode_handle'.
+
 The majority of drivers should use the linear map.
 
 ==== Tree ====
 irq_domain_add_tree()
+irq_domain_create_tree()
 
 The irq_domain maintains a radix tree map from hwirq numbers to Linux
 IRQs.  When an hwirq is mapped, an irq_desc is allocated and the
@@ -95,6 +102,11 @@ since it doesn't need to allocate a table as large as the largest
 hwirq number.  The disadvantage is that hwirq to IRQ number lookup is
 dependent on how many entries are in the table.
 
+irq_domain_add_tree() and irq_domain_create_tree() are functionally
+equivalent, except for the first argument is different - the former
+accepts an Open Firmware specific 'struct device_node', while the latter
+accepts a more general abstraction 'struct fwnode_handle'.
+
 Very few drivers should need this mapping.
 
 ==== No Map ===-