spi: pic32-sqi: silence array overflow warning

We read one element beyond the end of the array when we access
"rdesc[i + 1]" so it causes a static checker warning.  It's harmless
because we write over it again on the next line.  But let's just silence
the warning.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Purna Chandra Mandal <purna.mandal@microchip.com>
Signed-off-by: Mark Brown <broonie@kernel.org>