Confusion here is that original ROM has two functions:
* SPIReadModeCnfig() - sets mode, calls enable_qio_mode/disable_qio_mode
* SPIMasterReadModeCnfig() - As above, but doesn't set QIO mode in status register
However we never want to use the ROM method to set/clear QIO mode flag, as not all flash chips work this way. Instead we
do it in flash_qio_mode.c in bootloader.
So in both cases (ROM or "patched ROM") we now call SPIMasterReadModeCnfig(), which is now named
esp_rom_spiflash_config_readmode().
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