Patch merged into coreboot/master: riscv: Unify SBI call implementations under arch/riscv/

the following patch was just integrated into master:
commit 99f2f113ec397dd042dcaa23c47123f3def19ebc
Author: Jonathan Neuschäfer 
Date:   Fri Oct 28 00:25:02 2016 +0200

riscv: Unify SBI call implementations under arch/riscv/

Note that currently, traps are only handled by the trap handler
    installed in the bootblock. The romstage and ramstage don't override it.

TEST=Booted emulation/spike-qemu and lowrisc/nexys4ddr with a linux
         payload. It worked as much as before (Linux didn't boot, but it
         made some successful SBI calls)

Change-Id: Icce96ab3f41ae0f34bd86e30f9ff17c30317854e
    Signed-off-by: Jonathan Neuschäfer 
    Reviewed-on: https://review.coreboot.org/17057
    Tested-by: build bot (Jenkins)
    Reviewed-by: Martin Roth 
    Reviewed-by: Ronald G. Minnich

See https://review.coreboot.org/17057 for details.

-gerrit