staging: comedi: tests: ni_routes_test: Avoid CamelCase: <RVi>

staging: comedi: tests: ni_routes_test: Avoid CamelCase: <RVi>

Rename the `RVi` macro to `RVI` to avoid this checkpatch.pl issue:

CHECK: #27: FILE: drivers/staging/comedi/drivers/tests/ni_routes_test.c:27:
+#define RVi(table, src, dest)	((table)[(dest) * NI_NUM_NAMES + (src)])

Cc: Spencer E. Olson <olsonse@umich.edu>
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20210407140142.447250-4-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>