include: fpga: adi-axi-common.h: fixup whitespace tab -> space

The initial version use a tab between '#define' & 'ADI_AXI_REG_VERSION'.
This changes it to space. The change is purely cosmetic.
Acked-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>