samus: Increase charger task stack size
samus: Increase charger task stack size

Increase the stack size for the charger task to work around I2C
battery communication issues.

BUG=chrome-os-partner:29839
BRANCH=None
TEST=watch for I2C0 transation failures and ensure that the charger
task does not stack overflow and reset the EC+system.

Change-Id: Iabae3e2c302b68eb9e25a604dd72ef48128866df
Signed-off-by: Duncan Laurie <70662b43bc1a20b57ded72a2b08be88dd0da4841@chromium.org>
Signed-off-by: Alec Berg <1a4429eeda29095a12e19a73405f80f5b7f37a63@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/205142
Reviewed-by: Vincent Palatin <70a9964ec8fd10b0b08fcc8623c2add25ddf99ac@chromium.org>

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