clk: x86: Add system specific quirk to mark clocks as critical

Since commit 648e921888 ("clk: x86: Stop marking clocks as
CLK_IS_CRITICAL"), the pmc_plt_clocks of the Bay Trail SoC are
unconditionally gated off. Unfortunately this will break systems where these
clocks are used for external purposes beyond the kernel's knowledge. Fix it
by implementing a system specific quirk to mark the necessary pmc_plt_clks as
critical.

Fixes: 648e921888 ("clk: x86: Stop marking clocks as CLK_IS_CRITICAL")
Signed-off-by: David Müller <dave.mueller@gmx.ch>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

include/linux/platform_data/x86/clk-pmc-atom.h

@@ -35,10 +35,13 @@ struct pmc_clk {
  *
  * @base:	PMC clock register base offset
  * @clks:	pointer to set of registered clocks, typically 0..5
+ * @critical:	flag to indicate if firmware enabled pmc_plt_clks
+ *		should be marked as critial or not
  */
 struct pmc_clk_data {
 	void __iomem *base;
 	const struct pmc_clk *clks;
+	bool critical;
 };
 
 #endif /* __PLATFORM_DATA_X86_CLK_PMC_ATOM_H */