qemu: fix /cfg mount failure due to missing mkfs.ext4 in PATH

The cfg.ext4 disk image was created but not formatted because mkfs.ext4
wasn't found. As sbin is not in PATH for an unprivileged user in
Debian.

This caused the VM boot to fail with "No persistent storage found for /cfg".

Signed-off-by: Richard Alpe <[email protected]>

Author: rical

board/common/qemu/run.sh

@@ -19,6 +19,9 @@
 #
 # shellcheck disable=SC3037
 
+# Add /sbin to PATH for mkfs.ext4 and such (not default in debian)
+export PATH="/sbin:/usr/sbin:$PATH"
+
 qdir=$(dirname "$(readlink -f "$0")")
 imgdir=$(readlink -f "${qdir}/..")
 prognm=$(basename "$0")
@@ -174,6 +177,8 @@ rw_args()
 {
     [ "$CONFIG_QEMU_RW" ] ||  return
 
+    command -v mkfs.ext4 >/dev/null || die "$prognm: cannot find mkfs.ext4"
+
     if ! [ -f "aux.ext4" ]; then
 	dd if=/dev/zero of="aux.ext4" bs=1M count=1 >/dev/null 2>&1
 	mkfs.ext4 -L aux "aux.ext4" >/dev/null 2>&1