mkbp_event,include/config.h: Clarify MKBP delivery method.

Now we have two MKBP delivery methods:
1. define CONFIG_MKBP_USE_HOST_EVENT to notify via host event
2. undef CONFIG_MKBP_USE_HOST_EVENT to notify via GPIO interrupt

It may become more complicated if new notification methods introduced.
e.g.: mt_scp uses IPI, rather than host event and GPIO interrupt.
This CL does:
1. add CONFIG_MKBP_USE_GPIO to explicilty declare that MKBP event are
   sent via GPIO interrupt.
2. CONFIG_MKBP_USE_CUSTOM for boards which have custmized methods.
3. Remove weak attribute in mkbp_set_host_active (which can be done
   with CONFIG_MKBP_USE_CUSTOM now.
4. Removes mkbp_set_host_active function in board Nocturne.  It only
   deliver MKBP events through GPIO interrupt now.

BRANCH=None
BUG=b:120808999
TEST=grep -rn "CONFIG_MKBP_USE_GPIO\|EC_INT_L" board/ baseboard/ and
     see the result is reasonable:
     1. EC_INT_L must be 1-to-1 mapped to define CONFIG_MKBP_USE_GPIO in
        every board, except that meep, yorp, ampton which are defined in
        baseboard octopus.
     2. undef CONFIG_MKBP_USE_GPIO in bip and casta, which use host
        event, but also have baseboard octopus.

Change-Id: I4af6110e4fd3c009968075c3623ef2d91cbd770b
Signed-off-by: Yilun Lin <yllin@google.com>
Reviewed-on: https://chromium-review.googlesource.com/1490794
Commit-Ready: Jett Rink <jettrink@chromium.org>
Tested-by: Yilun Lin <yllin@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-by: Jett Rink <jettrink@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1719541
Reviewed-by: Edward Hill <ecgh@chromium.org>
Tested-by: Edward Hill <ecgh@chromium.org>
Commit-Queue: Edward Hill <ecgh@chromium.org>

0 files changed, 0 insertions, 0 deletions