The issue that cache entries are not invalidated correctly sometimes
can also be reproduced for non-encrypted flash as well.
This change updates the workaround to do Cache_Flush, enabling it for
non-encrypted flash, and adds a unit test.
Partition/SPI/OTA docs & OTA new functionality
* Update partition, SPI flash & OTA docs to reflect functionality changes
* Refactor OTA implementation to perform checks mentioned in API doc
* Add new functions to OTA API: esp_ota_get_running_partition() & esp_ota_get_next_update_partition() functions
* Add spi_flash_cache2phys() & spi_flash_phys2cache() functions to support esp_ota_get_running_partition()
See merge request !513
Seems doing certain kinds of short reads while flash encryption is
enabled will return stale data. This fixes it, but is probably a
little heavy-handed performance wise.
Without this, it's possible for stale information to be read from
cache via mmap, even if the MMU table entry had been invalidated
prior to writing flash (if the same MMU table entry was re-used after
writing flash.)
