efi_loader: device_path: check against file path length

device_path strcuture has 2 bytes of "length" field, and so
file path length should not exceed this limit, 65535.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
1 file changed