clk: lpc32xx: Set name of regmap_config

We are now allowing to register debugfs without a valid device, and not
having a valid name will end up using "dummy*" to create debugfs dir.

Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Acked-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>