espi-control: Add program to disable eSPI

This commit introduces a program that can disable and re-enable eSPI on
a Nuvoton BMC.

Tested:
- Ran "npcm7xx_espi_control -d", and confirmed that IPMI stopped
  working.
- Ran "npcm7xx_espi_control", and confirmed that IPMI started working
  again.

Change-Id: I9637ac4d84b82931f107946ff53e7ef16a965d25
Signed-off-by: John Wedig <johnwedig@google.com>
diff --git a/.gitignore b/.gitignore
index fbedebd..27676e3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,6 +2,7 @@
 subprojects/*
 !subprojects/acpi-power-state-daemon/
 !subprojects/dhcp-done/
+!subprojects/espi-control/
 !subprojects/libcr51sign/
 !subprojects/metrics-ipmi-blobs/
 !subprojects/ncsid/