efi_loader: disk: add efi_disk_is_removable()

This helper function will be used to determine if the device is
removable media, initially for handling a short-path loading.

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