1. Original register mapping for LAN8720 has some registers that doesn't exist/support.
So just remove them, and fix the power and init function for LAN8720.
2. GPIO16 and GPIO17 is occupied by PSRAM, so only ETH_CLOCK_GPIO_IN mode is supported in that case if using PSRAM.
3. Fix bug of OTA failing with Ethernet
4. Fix bug of multicast with Ethernet
5. Fix potential memory leak
1. remove use EID to distinguish psram voltage
2. 1V8 64Mbit psram and 3V3 64Mbit psram use the same psram driver(standard spi interface)
3. set cs hold time register as 1
1. Add reading psram EID.
2. Configure different clock mode for different EID.
3. add API to get psram size and voltage.
4. Remove unnecessary VSPI claim.
For 32MBit@1.8V and 64MBit@3.3V psram, there should be 2 extra clock cycles after CS get high level.
For 64MBit@1.8 psram, we can just use standard SPI protocol to drive the psram. We also need to increase the HOLD time for CS in this case.
EID for psram:
32MBit 1.8v: 0x20
64MBit 1.8v: 0x26
64MBit 3.3v: 0x46
Some frameworks based on ESP-IDF need to be able to decide whether to
initialize SPI RAM after the application has started. This change splits
out part of esp_spiram_init which manipulate cache MMU into a separate
function. Applications can disable cache, call esp_spiram_init_cache,
re-enable cache, and then call esp_spiram_init.
Disabling and re-enabling the cache can be achieved using functions
provided in esp_spi_flash.h.
