When SIM_SPI is valid, a specified Linux SPI device ‘spidevN.P’(N is bus number and P is CS number) is attached to nuttx simulator, shown as 'spi0' under /dev. One may type spi command (need SPITOOL valid) in NSH to control the Linux SPI and exchange data, other devices such sensors can use it to debug in simulator on a Ubuntu PC. Note that a USB<>SPI module (e.g. CH341A/B) should be plugged in to achieve Linux SPI ports.
Change-Id: I275b2c2bbf6d14bcdf514c89efb9a2264d69e9a3
Signed-off-by: liucheng5 <liucheng5@xiaomi.com>
