mfd: hi655x-pmic: Fix missing return value check for devm_regmap_init_mmio_clk

mfd: hi655x-pmic: Fix missing return value check for devm_regmap_init_mmio_clk

BugLink: https://bugs.launchpad.net/bugs/1839036
[ Upstream commit 7efd105c27fd2323789b41b64763a0e33ed79c08 ]

Since devm_regmap_init_mmio_clk can fail, add return value checking.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Chen Feng <puck.chen@hisilicon.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>