EC:KBC: Wait until LPC host senses the IRQ and gets the character.
EC:KBC: Wait until LPC host senses the IRQ and gets the character.

BRANCH=master
BUG=chrome-os-partner:29139
TEST=Buiid an EC FW image and run on Rambi to test if key loss is
improved and any side effect somes with this change. Need more test
units to confirm this.
Signed-off-by: Kenji Chen <0bf7525e08375703f50ef5500dc31c55f4ea7d0b@intel.com>
Change-Id: I2399e33d2ca3defe8cd9b1f94ab0af1db7f84635
Reviewed-on: https://chromium-review.googlesource.com/225557
Reviewed-by: Randall Spangler <62698fdbb84d1779579ee80c3f39fac22017e5bc@chromium.org>
Reviewed-by: Mohammed Habibulla <8a503cc33e9ca0fe4680ecfe79b9e9ed9e1c57a0@chromium.org>

coreboot/chrome-ec,fourier49/BZ_DEV_EC,fourier49/BZ_DEV_EC,coreboot/chrome-ec,fourier49/BIZ_EC,eatbyte/chromium-ec,akappy7/ChromeOS_EC_LED_Diagnostics,coreboot/chrome-ec,coreboot/chrome-ec,fourier49/BZ_DEV_EC,md5555/ec,fourier49/BZ_DEV_EC,mtk09422/chromiumos-platform-ec,akappy7/ChromeOS_EC_LED_Diagnostics,akappy7/ChromeOS_EC_LED_Diagnostics,fourier49/BIZ_EC,mtk09422/chromiumos-platform-ec,mtk09422/chromiumos-platform-ec,eatbyte/chromium-ec,md5555/ec,coreboot/chrome-ec,coreboot/chrome-ec,md5555/ec,fourier49/BIZ_EC,mtk09422/chromiumos-platform-ec,fourier49/BIZ_EC,md5555/ec,longsleep/ec,longsleep/ec,eatbyte/chromium-ec,longsleep/ec,longsleep/ec,akappy7/ChromeOS_EC_LED_Diagnostics,akappy7/ChromeOS_EC_LED_Diagnostics,eatbyte/chromium-ec