regmap: spi: Set regmap max raw r/w from max_transfer_size

Set regmap raw read/write from spi max_transfer_size
so regmap_raw_read/write can split the access into chunks

Signed-off-by: Lucas Tanure <tanureal@opensource.cirrus.com>
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
[André: fix build warning]
Signed-off-by: André Almeida <andrealmeid@collabora.com>
Link: https://lore.kernel.org/r/20211021132721.13669-1-andrealmeid@collabora.com


Signed-off-by: Mark Brown <broonie@kernel.org>