Remove unused install_toolchain.sh script

This script is unused and doesn't add functionality beyond wrapping
util/get-toolchain.py. Remove it.

Signed-off-by: Philipp Wagner <phw@lowrisc.org>
diff --git a/ci/install_toolchain.sh b/ci/install_toolchain.sh
deleted file mode 100755
index 29bd610..0000000
--- a/ci/install_toolchain.sh
+++ /dev/null
@@ -1,24 +0,0 @@
-#!/bin/bash
-
-echo "Setting up RISC-V toolchain."
-readonly DEFAULT_RISCV_TOOLS=/tools/riscv
-readonly DEFAULT_RISCV_TOOLS_VERSION=latest
-readonly DEFAULT_TOOLCHAIN_REQUEST_UPDATE=false
-
-TOOLCHAIN_PATH="${TOOLCHAIN_PATH:-$DEFAULT_RISCV_TOOLS}"
-TOOLCHAIN_VERSION="${TOOLCHAIN_VERSION:-$DEFAULT_RISCV_TOOLS_VERSION}"
-REQUEST_UPDATE="${REQUEST_UPDATE:-$DEFAULT_TOOLCHAIN_REQUEST_UPDATE}"
-
-if [[ ! -d "${TOOLCHAIN_PATH}/bin" ]]; then
-  echo "Unable to find toolchain at: ${TOOLCHAIN_PATH}."
-  REQUEST_UPDATE=true
-fi
-
-if [[ "${REQUEST_UPDATE}" = true ]]; then
-  echo "Syncing toolchain directory to TOOLCHAIN_VERSION=${TOOLCHAIN_VERSION}"
-  util/get-toolchain.py \
-    --target-dir="${TOOLCHAIN_PATH}" \
-    --release-version="${TOOLCHAIN_VERSION}" \
-    --update \
-    --force
-fi