of: platform: populate /firmware/ node from of_platform_default_populate_init()

of: platform: populate /firmware/ node from of_platform_default_populate_init()

Since "/firmware" does not have its own "compatible" property as it's
just collection of nodes representing firmware interface, it's sub-nodes
are not populated during system initialization.

Currently different firmware drivers search the /firmware/ node and
populate the sub-node devices selectively. Instead we can populate
the /firmware/ node during init to avoid more drivers continuing to
populate the devices selectively.

To generalize the solution this patch populates the /firmware/ node
explicitly from of_platform_default_populate_init().

Cc: Arnd Bergmann <[email protected]>
Cc: Rob Herring <[email protected]>
Signed-off-by: Sudeep Holla <[email protected]>
Acked-by: Rob Herring <[email protected]>
Acked-by: Bjorn Andersson <[email protected]>
Tested-by: Bjorn Andersson <[email protected]>
Signed-off-by: Andy Gross <[email protected]>