Bootloader used to calculate the number of cache pages assuming that
load address was aligned, while in reality load address for DROM and
IROM was offset by 0x20 bytes from the start of 64kB page. This
caused the bootloader to map one less page if the size of the image
was 0x4..0x1c less than a multiple of 64kB.
Reported in https://esp32.com/viewtopic.php?f=13&t=6952.
* App access functions are all flash encryption-aware
* Documentation for flash encryption
* Partition read/write is flash aware
* New encrypted write function
