RDMA/bnxt_re: Fix Kconfig indentation

Adjust indentation from spaces to tab (+optional two spaces) as in coding
style with command like:
	$ sed -e 's/^        /\t/' -i */Kconfig

Link: https://lore.kernel.org/r/20191120134138.15245-1-krzk@kernel.org


Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>