qcacmn: Fix -Wmissing-prototypes in if_pci.c

We want to enable the compiler's -Wmissing-prototypes switch, but
there is existing code in if_pci.c that is generating warnings.  Fix
these warnings by making the following functions static:
	hif_enable_pci()
	hif_register_bmi_callbacks()
	hif_ce_interrupt_handler()

Change-Id: Iaf30be455ce537fabc85dc973ceb3f1b820d29d9
CRs-Fixed: 1107494
1 file changed