lib/vboot_ui_menu: Consider volume buttons in vb2_update_selection
lib/vboot_ui_menu: Consider volume buttons in vb2_update_selection

vb2_update_selection considered only KEY_UP and KEY_DOWN inputs to
update the selection. This resulted in volume buttons not working on
firmware screen to update the selection. Add volume buttons as valid
inputs in vb2_update_selection.

BUG=b:64839396
BRANCH=None
TEST=Verified that volume buttons work on firmware screen.

Change-Id: I08bfa91eafb170fb450649a2abaafe7f4d58e17b
Signed-off-by: Furquan Shaikh <6be5c96c464778f89679b1062a2e0a6af93d2aa5@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/621787
Reviewed-by: Aaron Durbin <af0622ab041e8b0f8e5819838dcc93898196e71f@chromium.org>
Reviewed-by: Shelley Chen <ab7b8cc85923339aed379eb1c5cc4dccfd2eb3d7@chromium.org>

coreboot/vboot,coreboot/vboot,coreboot/vboot,coreboot/vboot,coreboot/vboot