spi_flash: fix initialization failure when ex_flash with psram on non-SPI1 bus.
spi_flash: fix initialization failure when ex_flash with psram on
non-SPI1 bus.

Close https://github.com/espressif/esp-idf/issues/4379

espressif/esp-idf,espressif/esp-idf,espressif/esp-idf,espressif/esp-idf