hammer: Enable eel GMR function

Add eel to variants to enable GMR sensor for tablet mode function.

BUG=b:199033321
TEST=make
BRANCH=trogdor

Signed-off-by: Siyu Qin <[email protected]>
Change-Id: I5aeea9ec67f9f28b9e823876cf89a2dc8998f114
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3143406
Reviewed-by: wen zhang <[email protected]>
Reviewed-by: Ting Shen <[email protected]>
Commit-Queue: Ting Shen <[email protected]>

Author: qinsiyu-dev

board/hammer/variants.h

@@ -174,7 +174,8 @@
 
 /* GMR sensor for tablet mode detection */
 #if defined(BOARD_DON) || defined(BOARD_MASTERBALL) || \
-    defined(BOARD_MOONBALL) || defined(BOARD_WHISKERS)
+    defined(BOARD_MOONBALL) || defined(BOARD_WHISKERS) || \
+    defined(BOARD_EEL)
 #define CONFIG_GMR_TABLET_MODE
 #endif