clk: mediatek: Mark bus and DRAM related clocks as critical
Currently, DRAM-related clocks are not marked with CLK_IS_CRITICAL
for MT6797. This causes memory corruption when the system is
booted without clk_ignore_unused.
This patch marks MUX ddrphycfg_sel as well as gates infra_dramc_f26m
and infra_dramc_b_f26m as CLK_IS_CRITICAL.