Commit fd4ebc07 ("regmap: Hold the regmap lock when allocating and
freeing the cache") introduced a locking around the allocating and
freeing a regmap cache, so adjust the memory allocation flags to the ones
given in the regmap configuration instead of the hardcoded GFP_KERNEL.

This fixes the "BUG: sleeping function called from invalid context"
introduced by the mentioned commit.

Fixes: fd4ebc07 ("regmap: Hold the regmap lock when allocating and freeing the cache")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://patch.msgid.link/20240828122834.3778031-1-m.szyprowski@samsung.comSigned-off-by: Mark Brown <broonie@kernel.org>