unmap memory mapped with devm_ioremap_resource

[Adrian Fiergolski]

Hello,

I am extending xilinx-hls driver 
(https://github.com/Xilinx/linux-xlnx/blob/master/drivers/media/platform/xilinx/xilinx-hls.c) 
to support of_overlay.

In order to reflect in the driver changes being applied by the overlay 
to the device tree, I need to unmap first the memory mapped with 
devm_ioremap_resource. How to do it properly?

I think it's uncommon, as normally kernel (devm_* functions) manages 
those resources itself with devres, so I can't find inspiration in other 
drivers.

Regards,
Adrian