There used to be dummy phase before out phase in common command
transactions. This corrupts the data.
The code before never actually operate (clear) the QE bit, once it finds
the QE bit is set. It's hard to check whether the QE set/disable
functions work well.
This commit:
1. Cancel the dummy phase
2. Set and clear the QE bit according to chip settings, allowing tests
for QE bits. However for some chips (Winbond for example), it's not
forced to clear the QE bit if not able to.
3. Also refactor to allow chip_generic and other chips to share the same
code to read and write qe bit; let common command and read command share
configure_host_io_mode.
4. Rename read mode to io mode since maybe we will write data with quad
mode one day.
