For config-only components, component.mk should now contain "COMPONENT_CONFIG_ONLY := 1"
Also refactored some of the generation of linker paths, library list. This required cleaning up the way the bootloader
project works, it's now mostly independent from the parent.
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().
1) fixed SPI_read_status: added check for flash busy flag in matrix mode
2) fixed SPI_page_program: enable write before writing data to SPI FIFO
3) SPI flash ROM funcs replacement is controlled via menuconfig option
