drm/bridge: samsung-dsim: add ability to define clock names for every variant

Presently, all devices refer to clock names from a single array. The
only controlling parameter is the number of clocks (num_clks field of
samsung_dsim_driver_data) which uses the first n clocks of that array.
As new devices are added, this approach turns out to be cumbersome.

Separate the clock names in individual arrays required by each variant,
in a struct clk_bulk_data. Add a pointer field to the driver data struct
which points to their respective clock names, and rework the clock usage
code to use the clk_bulk_* API instead.

Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
Signed-off-by: Inki Dae <inki.dae@samsung.com>