chip/npcx: Close LPC window before sysjump
chip/npcx: Close LPC window before sysjump

Before performing a sysjump, ensure that:
1. LPC interrupts are disabled : Ensures interrupts are not taken until
next enable.
2. LPC window is closed by writing 0xfffffff8 to window base addresses:
Prevents any memory corruption by host.

BUG=chrome-os-partner:57642
BRANCH=None
TEST=Verfied that LPC communication works after sysjump to RW.

Change-Id: I7b7826b2544f1c94cfa9c96b6ac82bc3517b1820
Signed-off-by: Furquan Shaikh <6be5c96c464778f89679b1062a2e0a6af93d2aa5@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/388755
Reviewed-by: Aaron Durbin <af0622ab041e8b0f8e5819838dcc93898196e71f@chromium.org>
Reviewed-by: Mulin Chao <6bbc5af053a1dfdc363be6857f30de4ac3bcbd16@nuvoton.com>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec