platform/x86: thinkpad_acpi: Change the keymap for Favorites hotkey

The keycode KEY_FAVORITES(0x16c) used in thinkpad_acpi driver is too
big (out of range > 255) for xorg to handle.
xkeyboard-config has already mapped KEY_BOOKMARKS(156) to
XF86Favorites:

keycodes/evdev:
    <I164> = 164;   // #define KEY_BOOKMARKS           156

symbols/inet:
    key <I164>   {      [ XF86Favorites         ]       };

So change the keymap to KEY_BOOKMARKS for Favorites hotkey.

Signed-off-by: Zhang Xianwei <zhang.xianwei8@zte.com.cn>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>