platsupport: TK1 SPI: Silence build warning

platsupport: TK1 SPI: Support multiple slaves in a very crude fashion

Change 1 << * to BIT(*) in some cases

fix licenses

libplatsupport: Unify Chip select enum variants

Was introduced in pr #79. Previously these were defined per platform,
and when defining globally for TK1 there was a name conflict with
exynos.

libplatsupport: Fix tk1 spi fifo init

libplatsupport: Remove prefix from spi driver vars

libplatsupport: A couple more changes for software/hardware chip select

libplatsupport: add chipselect function injection

The TK1 spi driver is currently only used in a CAmkES application that
was managing the chip select functionality at the component level. This
commit moves the CS functionality into the driver by allowing the CAmkES
application to initialise the driver with the cs function pointer that
the driver can then use more intelligently.

libplatsupport: Rewrite TK1 spi driver

The previous TK1 spi driver had a series of issues which it made it
easier to replace rather than patch.

libplatsupport: SELFOUR-726 Use PAD_STRUCT_BETWEEN in spi.c

Integrating changes from DARPA repo to trunk