efi_loader: reduce noisiness if ESP is missing

EFI variables can be stored in a file on the EFI system partition. If that
partition is missing we are writing two error messages per variable. This
is too noisy.

Just warn once about the missing ESP.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
1 file changed