spi_master: Introduce SPI_MASTER_4BA feature flags

Add a feature flag SPI_MASTER_4BA to `struct spi_master` that advertises
programmer-side support for 4-byte addresses in generic commands (and
read/write commands if the master uses the default implementations). Set
it for all masters that handle commands address-agnostic.

Another feature flag SPI_MASTER_4BA_STATEFUL tells us that the program-
mer keeps the flash chip powered between commands, i.e. the flash keeps
its volatile state. This is needed to decide if we can use stateful 4BA
modes.

Don't prefer native 4BA instructions if the master doesn't support them.

Change-Id: Ife66e3fc49b9716f9c99cad957095b528135ec2c
Signed-off-by: Nico Huber <nico.h@gmx.de>
---
M bitbang_spi.c
M buspirate_spi.c
M ch341a_spi.c
M dummyflasher.c
M ft2232_spi.c
M linux_spi.c
M programmer.h
M serprog.c
M spi25.c
9 files changed, 32 insertions(+), 4 deletions(-)