stm32: Drop key scan masks
stm32: Drop key scan masks

The masks were intended to be used to ignore certain keys in the matrix to
help with de-ghosting of keys. Since this is done on the AP anyway, there
really isn't any need for them. Punt.

BUG=chrome-os-partner:12179
BRANCH=snow
TEST=manual
Build and boot into kernel, see that keyboard still works.

Change-Id: I00d1b761d24ab503c66439b095a8336fff5d5db6
Signed-off-by: Simon Glass <c00b0378376498bd9cd974c388df8854c0131d27@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/34657

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