efi_get_variable() always stores an extra zero byte after the output data.
When the returned data size matches the output buffer size, the extra zero
byte is stored past the end of the output buffer.
Signed-off-by: Ivan Gorinov <ivan.gorinov@intel.com> Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Signed-off-by: Alexander Graf <agraf@suse.de>