npcx: lpc: Fix KB malfunction after power-key off and then on

The original thought of setting LRESET_PLTRST_MODE to 1 is to remove the
need to reinitialize host module registers whenever LRESET# occurs in
order to save time when boot-up.

However, some of these registers will be reset by core domain reset. It
means every time LRESET is de-asserted, we need to initialize the host
setting again. Therefore, setting LRESET_PLTRST_MODE to 1 is unnecessary
and sometimes dangerous. If BIOS believes LRESET will reset ec's host
state machine to default but ec not, it will cause unexpected behavior.

Modified drivers:
1. lpc.c: allow LRESET/PLTRST generate host domain reset

BUG=chrome-os-partner:60211
BRANCH:none
TEST=make buildall. run "dut-control pwr_button:press; sleep 11; dut-control
pwr_button:release; sleep 7; dut-control pwr_button:press; sleep 1;
dut-control pwr_button:release". Verify keyboard works normally.

Change-Id: I94d428cde69f828468547c44844983f25686ea04
Signed-off-by: CHLin <CHLIN56@nuvoton.com>
Reviewed-on: https://chromium-review.googlesource.com/417745
Commit-Ready: Daisuke Nojiri <dnojiri@chromium.org>
Tested-by: Daisuke Nojiri <dnojiri@chromium.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>

chip/npcx/lpc.c

@@ -811,9 +811,6 @@ void host_register_init(void)
 	/* enable SHM */
 	lpc_sib_write_reg(SIO_OFFSET, 0x30, 0x01);
 
-	/* An active LRESET or PLTRST does not generate host domain reset */
-	SET_BIT(NPCX_RSTCTL, NPCX_RSTCTL_LRESET_PLTRST_MODE);
-
 	CPRINTS("Host settings are done!");
 
 }