clk: mxl: Switch from direct readl/writel based IO to regmap based IO

stable inclusion
from stable-v5.10.170
commit 072eb5fbd69c1e566e1c9c4b08c199dbbf1dc181
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7V9QX

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=072eb5fbd69c1e566e1c9c4b08c199dbbf1dc181



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[ Upstream commit 03617731 ]

Earlier version of driver used direct io remapped register read
writes using readl/writel. But we need secure boot access which
is only possible when registers are read & written using regmap.
This is because the security bus/hook is written & coupled only
with regmap layer.

Switch the driver from direct readl/writel based register accesses
to regmap based register accesses.

Additionally, update the license headers to latest status.

Reviewed-by: Yi xin Zhu <yzhu@maxlinear.com>
Signed-off-by: Rahul Tanwar <rtanwar@maxlinear.com>
Link: https://lore.kernel.org/r/2610331918206e0e3bd18babb39393a558fb34f9.1665642720.git.rtanwar@maxlinear.com


Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Stable-dep-of: 106ef3bd ("clk: mxl: Fix a clk entry by adding relevant flags")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: zhaoxiaoqiang11 <zhaoxiaoqiang11@jd.com>