regmap: Correct comparison in regmap_cached

[ Upstream commit 71df179363a5a733a8932e9afb869760d7559383 ]

The cache pointer points to the actual memory used by the cache, as the
comparison here is looking for the type of the cache it should check
against cache_type.

Fixes: 1ea975cf ("regmap: Add a function to check if a regmap register is cached")
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>