touchpad_elan: ignore unknown ic_type
touchpad_elan: ignore unknown ic_type

Unknown ic_type is not a fatal error, it only affects fw update, but not
other usual touchpad functions. We can ignore this error to keep
touchpad working.

BUG=none
TEST=EC able to ignore the unknown ic type error
     [1.299220 elan_tp_init: ic_type:1500.]
     [1.299820 elan_tp_init: iap_version:0204.]
     [1.299976 unknown ic_type: 21]
     [1.302292 max=3282/1793 width=82/76 adj=0 dpi=800/800]
     [1.302570 *** TP mismatch!]
     [1.303245 elan_tp_init:0]
BRANCH=trogdor

Signed-off-by: Ting Shen <c671d3efec3d7e7e285f3788bf0d1ba4c8605b78@google.com>
Change-Id: Ic0471989bb669482deee973c0e4495a65f6928f4
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2874947
Reviewed-by: Wai-Hong Tam <04b587fdf5845741a0c5a8b9cd59ca72d73ef8fc@google.com>
Commit-Queue: Ting Shen <c671d3efec3d7e7e285f3788bf0d1ba4c8605b78@chromium.org>
Tested-by: Ting Shen <c671d3efec3d7e7e285f3788bf0d1ba4c8605b78@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec