msm: face detect: use misc irq for halt and core interrupts

When face detect engine have support for misc irq,
driver can handle core and halt on same irq line.

This change removes support for both interrupts when halt
is required and register for only one interrupt at a time.

Change-Id: Idb4604351f1026b2c95774914190911c0fb2c138
Signed-off-by: Gjorgji Rosikopulos <grosik@codeaurora.org>