pmdomain: 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://lore.kernel.org/r/20250813161517.4746-15-wsa+renesas@sang-engineering.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Author: Wolfram Sang

drivers/pmdomain/imx/gpc.c

@@ -343,7 +343,6 @@ static const struct regmap_config imx_gpc_regmap_config = {
 	.rd_table = &access_table,
 	.wr_table = &access_table,
 	.max_register = 0x2ac,
-	.fast_io = true,
 };
 
 static struct generic_pm_domain *imx_gpc_onecell_domains[] = {