regulator: remove unneeded 'fast_io' parameter in regmap_config

When using MMIO with regmap, fast_io is implied. No need to set it
again.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://patch.msgid.link/20250813161517.4746-16-wsa+renesas@sang-engineering.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: Wolfram Sang

drivers/regulator/qcom-refgen-regulator.c

@@ -94,7 +94,6 @@ static const struct regmap_config qcom_refgen_regmap_config = {
 	.reg_bits = 32,
 	.reg_stride = 4,
 	.val_bits = 32,
-	.fast_io = true,
 };
 
 static int qcom_refgen_probe(struct platform_device *pdev)