board_r: run scsi init() on ARM too

This has been disabled for ARM in initr_scsi since that function was
introduced. However it works fine for me on Cubieboard and Cubietruck (with the
upcoming AHCI glue patch).

I also tested on two random ARM platforms which seem to define CONFIG_CMD_SCSI:
 - highbank worked fine (on midway hardware)
 - omap5_uevm built OK and I confirmed using objdump that things were as
   expected (i.e. the default weak scsi_init nop was used).

While there remove the mismatched comment from the #endif (omitting the comment
seems to be the prevailing style in this file).

Signed-off-by: Ian Campbell <ijc@hellion.org.uk>
Acked-by: Simon Glass <sjg@chromium.org>