fpga: region: remove unneeded of_node_get and put

Remove of_node_get/put in fpga_region_get/put.  Not
needed and will get in the way when I separate out
the common FPGA region code from Device Tree support
code.

Signed-off-by: Alan Tull <atull@kernel.org>
Acked-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>