The legacy driver can't handle the breaking change between esp chips
very well.
And it's not elegant to extend new feature like DMA, ETM.
The new driver can return a opaque handle for each RMT channel.
An obvious transaction concept was also introduced.
TX and RX functionalities are splited out.
The legacy driver is still available, but new feature won't be added.
Enable RMT_SUPPRESS_DEPRECATE_WARN if you don't want to see the
deprecated warnings.
1. Clean up clk usage in IDF, replace rtc_clk_xtal/apb_freq_get with
upper level API esp_clk_xtal/apb_freq
2. Fix small errors and wrong comments related to clock
3. Add clk_tree_defs.h to provide an unified clock id for each chip
Modify the NGed drivers to adopt new clock ids
peripheral enable/disable usually should be managed by driver itself,
so make it as espressif private APIs, not recommended for user to use it
in application code.
However, if user want to re-write the driver or ports to other platform,
this is still possible by including the header in this way:
"esp_private/peripheral_ctrl.h"
