rk3288: Add software I2C support

This patch adds the necessary platform glue to allow the use of
software-driven I2C bit banging on the RK3288. This is just a debugging
feature that can be used to reproduce certain I2C failure cases.

Also fix Makefile verstage linking for the feature and add some new
rk3288 IOMUX macros as needed.

BRANCH=None
BUG=None
TEST=Added "CONFIG_SOFTWARE_I2C=y" to configs/config.veyron_jerry,
wrapped Jerry's bootblock and verstage in software_i2c_attach/detach()
calls, confirmed that both PMIC and TPM could be driven correctly with
software I2C driver. Tried out different combinations of
software_i2c_wedge_ack() and software_i2c_wedge_read() on the PMIC and
observed transfer results with the hardware controller after reboot...
the worst that would happen is that the first register read-modify-write
(DCDC_ILMAX) would fail to read, but all later transfers would be fine.
Since that register is written twice (due to current BUCK1 ramp
implementation) and is not terribily important anyway, I think we don't
need to worry about wedging problems.

Change-Id: Iba801ee61d30fb1fd3aef8300612c67fa50c441b
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 24dfca9bab38a20c40ef0c2dd4c775b8d8f47487
Original-Change-Id: I96777300a57c85471bad20e23a455551e9970222
Original-Signed-off-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/247890
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/9757
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/device/Makefile.inc

@@ -25,5 +25,6 @@ subdirs-y += oprom dram
 ramstage-$(CONFIG_VGA_ROM_RUN) += pci_rom.c
 
 bootblock-$(CONFIG_SOFTWARE_I2C) += software_i2c.c
+verstage-$(CONFIG_SOFTWARE_I2C) += software_i2c.c
 romstage-$(CONFIG_SOFTWARE_I2C) += software_i2c.c
 ramstage-$(CONFIG_SOFTWARE_I2C) += software_i2c.c