hal: update combo device handling

If the wired headset/headphone/line devices are handled by
a different backend than speaker/earpiece devices, the combo
devices such as speaker+headphones can be split into individual
devices and enabled/disabled independently.

Bug: 21581860.

Change-Id: Icdd962a4dc1da536fe89c4de2202e7383275603d

hal: fix backend check routine for combo device

If there is path change between combo device and general device that
shares backend, previous device should be disabled before the new device
is enabled. Otherwise, by the race conditio, the new device would be
disabled by previous combo device
For example, when the previous device is 'speaker-and-headphone' and the new
devcie is 'voice-headphones', there is possibility that
'voice-headphones' get mute by disabling 'speaker-and-headphone'.

BUG=23916345

Change-Id: I765b3c0b6576f22c4aca290846d58dd1c6dfb8c5

hal msm8974: fix logic in platform_check_backends_match().

Fix logic error in if() condition in commit 9af4b91d
"hal: fix backend check routine for combo device"

BUG: 23916345
Change-Id: I587dd157ba34cad5f539d88e8161750f3e2b32c7