spi_master: Introduce SPI_MASTER_4BA feature flag

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.

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, 23 insertions(+), 3 deletions(-)