msm: usb_bam: remove obsolete IPA references

The USB BAM driver no longer interfaces with IPA nor HSIC/USB host
drivers. Remove the obsolete code. This includes suspend/resume
handling which was previously only called for IPA peer client.

Also fix definitions of usb_bam_{alloc,free}_fifos() to be
static inline to avoid compilation errors about multiple definitions
when CONFIG_USB_BAM is disabled.

Change-Id: I402c3596c33485e4649ecb241aee043867c4c4b7
Signed-off-by: Jack Pham <jackp@codeaurora.org>