clk: samsung: exynos850: Keep some crucial clocks running

clk: samsung: exynos850: Keep some crucial clocks running

Some clocks shouldn't be automatically disabled in clk_disable_unused(),
otherwise kernel hangs. Mark those clocks with:
  - CLK_IS_CRITICAL flag, when there won't be any consumers for that
    clock, but system can't function when it's gated
  - CLK_IGNORE_UNUSED flag, when consumer driver will be probably added
    later

That makes it possible to run the kernel without passing the
"clk_ignore_unused" param.

Next clocks were modified:
  - "gout_dpu_cmu_dpu_pclk":	CLK_IGNORE_UNUSED

    Will be enabled later in DSIM driver (Display Serial Interface
    Master).

  - "gout_gpio_peri_pclk":	CLK_IGNORE_UNUSED
    "gout_gpio_cmgp_pclk":	CLK_IGNORE_UNUSED
    "gout_gpio_hsi_pclk":	CLK_IGNORE_UNUSED

    Should be probably enabled in corresponding GPIO driver later, or
    made CLK_IS_CRITICAL. "gout_gpio_peri_clk" is actually used by LEDs
    on Exynos850-based dev board, so kernel hangs if this clock is not
    running. Other clocks were marked as "ignore unused" to prevent
    similar issues for other use cases or boards that might be added
    later.

  - "gout_cci_aclk":		CLK_IS_CRITICAL

    CCI (Cache Coherent Interconnect): obviously is critical.

  - "gout_gic_clk":		CLK_IS_CRITICAL

    GIC (Generic Interrupt Controller): obviously is critical.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20211121232741.6967-7-semen.protsenko@linaro.org