libpayload: usb: Allow direct instantiation of MMIO host controllers

The existing USB_MEMORY mechanism to instantiate non-PCI host
controllers is clunky and inflexible... most importantly, it doesn't
allow multiple host controllers of the same kind. This patch replaces it
with a function that allows payloads to directly instantiate as many
host controllers of whatever type they need.

Change-Id: Ic21d2016a4ef92c67fa420bdc0f0d8a6508b69e5
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/169454
Reviewed-by: Stefan Reinauer <reinauer@google.com>
(cherry picked from commit b6e95c39dd91f654f0a345f17b3196f56adf4891)
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6644
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

payloads/libpayload/include/usb/usb.h

@@ -240,6 +240,7 @@ typedef struct {
 	unsigned short wReportDescriptorLength;
 } __attribute__ ((packed)) hid_descriptor_t;
 
+hci_t *usb_add_mmio_hc(hc_type type, void *bar);
 hci_t *new_controller (void);
 void detach_controller (hci_t *controller);
 void usb_poll (void);