HID: wacom: Expect 'touch_max' touches if HID_DG_CONTACTCOUNT not present
HID: wacom: Expect 'touch_max' touches if HID_DG_CONTACTCOUNT not present

When introduced in commit 1b5d514, the check 'if (hid_data->cc_index >= 0)'
in 'wacom_wac_finger_pre_report' was intended to switch where the driver
got the expected number of contacts from: HID_DG_CONTACTCOUNT if the usage
was present, or 'touch_max' otherwise. Unfortunately, an oversight worthy
of a brown paper bag (specifically, that 'cc_index' could never be negative)
meant that the latter 'else' clause would never be entered.

The patch prior to this one introduced a way for 'cc_index' to be negative,
but only if HID_DG_CONTACTCOUNT is present in some report _other_ than the
one being processed. To ensure the 'else' clause is also entered for devices
which don't have HID_DG_CONTACTCOUNT on _any_ report, we add the additional
constraint that 'cc_report' be non-zero (which is true only if the usage is
present in some report).

Cc: 4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@vger.kernel.org
Signed-off-by: Jason Gerecke <e379142f391f1a25fba58f0c9c644cfc27aba8fd@wacom.com>
Signed-off-by: Jiri Kosina <ed58f755cc8caaf10c3e8c731a8b86fb8f13d6cb@suse.cz>

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