efi/apple-properties: Remove redundant attribute initialization from unmarshal_key_va...

efi/apple-properties: Remove redundant attribute initialization from unmarshal_key_value_pairs()

There is no need to artificially supply a property length and fake data
if property has type of boolean.

Remove redundant piece of data and code.

Reviewed-and-tested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20180308080020.22828-3-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>