cheriot: remove (incorrect) architecture specification

The cheriot toolchain does not need a -march specified (I blindly cribbed
it from previous work). Moreover specifying one that has 32 registers
is a bad idea.

Change-Id: Ia71a36f85d3f7f477cdbd33737a8e5c48c806ed8

platforms/cheri/riscv32/devices.bzl

diff --git a/platforms/cheri/riscv32/devices.bzl b/platforms/cheri/riscv32/devices.bzl
index 31a928f..4d08f56 100644
--- a/platforms/cheri/riscv32/devices.bzl
+++ b/platforms/cheri/riscv32/devices.bzl
@@ -11,7 +11,6 @@
             "//constraints/extension:cheri",
         ],
         substitutions = {
-            "ARCHITECTURE": "rv32imcxcheri",
             "ABI": "cheriot",
             "CMODEL": "medany",
             "ENDIAN": "little",
@@ -34,7 +33,6 @@
             "//constraints/extension:cheri-baremetal",
         ],
         substitutions = {
-            "ARCHITECTURE": "rv32imcxcheri",
             "ABI": "cheriot-baremetal",
             "CMODEL": "medany",
             "ENDIAN": "little",

platforms/cheri/riscv32/features/BUILD.bazel

diff --git a/platforms/cheri/riscv32/features/BUILD.bazel b/platforms/cheri/riscv32/features/BUILD.bazel
index 534d35a..fe073e5 100644
--- a/platforms/cheri/riscv32/features/BUILD.bazel
+++ b/platforms/cheri/riscv32/features/BUILD.bazel
@@ -20,7 +20,6 @@
             flag_groups = [
                 flag_group(
                     flags = [
-                        "-march=ARCHITECTURE",
                         "-mcpu=cheriot",
                         "-mabi=ABI",
                         "-mcmodel=CMODEL",