Merge branch 'bugfix/flash_write_single_core' into 'master'

spi_flash: fix protection issues

This MR fixes the two spi_flash related issues:

- esp_intr_noniram_{disable,enable} not being protected by spi_flash_op_{lock,unlock} in single core mode. This caused a safety assert to be triggered in esp_intr_noniram_disable.

- spi_flash_unlock not being protected by spi_flash_guard_{start,end}. This caused a conflict between SPI0 and SPI1 controllers when accessing SPI flash, manifesting in cache data corruption and IllegalInstruction exceptions, for some flash chips.

See merge request !522