Cleanup: only compile battery_vendor_params() when enabled
Cleanup: only compile battery_vendor_params() when enabled

Bolt uses Link's battery, but doesn't override the smart battery charge
profile with CONFIG_BATTERY_VENDOR_PARAMS. But the image still compiles and
includes the battery_vendor_params() function, although it's never called.

This CL stops doing that.

BUG=chrome-os-partner:18343
BRANCH=none
TEST=manual

Build all targets.

Confirm that Link still has battery_vendor_params():

  $ make BOARD=link
  $ nm build/link/common/charge_state.o  | grep vendor
           U battery_vendor_params
  $ nm build/link/driver/battery/link.o | grep vendor
  00000009 T battery_vendor_params
  $

Confirm that Bolt does not have battery_vendor_params():

  $ make BOARD=bolt
  $ nm build/bolt/common/charge_state.o  | grep vendor
  $ nm build/bolt/driver/battery/link.o | grep vendor
  $

Change-Id: I48a535208bdcfd3d2cb26f6f15a28a728dbe4d0b
Signed-off-by: Bill Richardson <129945214b1d548d8e49b6c29c43094f8c78057f@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/175731
Reviewed-by: Randall Spangler <62698fdbb84d1779579ee80c3f39fac22017e5bc@chromium.org>

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