Documentation: leds: MT6370: Use bullet lists for timing variables

Documentation: leds: MT6370: Use bullet lists for timing variables

The timing description contains list of timing pattern variables, but it
uses code block without indentation instead. Switch to bullet list as it
is better fit for this purpose.

While at it, substitute "load" for "duty" because the variables control
timing for current load into the device.

Link: https://lore.kernel.org/oe-kbuild-all/202303182310.tB1mUzU7-lkp@intel.com/
Fixes: 4ba9df04b7ac66 ("docs: leds: Add MT6370 RGB LED pattern document")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20230319074903.13075-4-bagasdotme@gmail.com