HID: hidp: fallback to input session properly if hid is blacklisted

This patch against kernel 3.7.0-rc8 fixes a kernel oops when turning on the
bluetooth mouse with id 0458:0058 [1].

The mouse in question supports both input and hid sessions, however it is
blacklisted in drivers/hid/hid-core.c so the input session is one that should
be used. Long ago (around kernel 3.0.0) some changes in the bluetooth
subsystem made the kernel do not fallback to input session when hid session is
not supported or blacklisted. This patch restore that behaviour by making the
kernel try the input session if hid_add_device returns ENODEV.

The patch exports hid_ignore() from hid-core.c so that it can be used in the
bluetooth subsystem.

[1] https://bugzilla.kernel.org/show_bug.cgi?id=39882



Signed-off-by: Lamarque V. Souza <lamarque@gmail.com>
Acked-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>