MIPS: ingenic: gcw0: Fix HP detection GPIO.

Previously marked as active high, but is in reality active low.

Cc: stable@vger.kernel.org
Fixes: b1bfdb66

 ("MIPS: ingenic: DTS: Update GCW0 support")
Signed-off-by: João H. Spies <jhlspies@gmail.com>
Tested-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>