core/riscv-rv32i: remove TODO from build.mk
core/riscv-rv32i: remove TODO from build.mk

We are able to build EC image with coreboot-sdk, so remove the TODO.

BUG=b:133639441
BRANCH=none
TEST=build board it83xx_evb with RISC-V core.

Change-Id: I21d5aa4735f38debb180277ac1acd9f7284298d1
Signed-off-by: Dino Li <338d523ecf3700bd86eb9c34d220f91911d2a18c@ite.com.tw>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1655218
Reviewed-by: Jett Rink <9d4aef0593e6843318d99df31597fb6153b89787@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec