usb: Hopefully resolve the red in 41f9285def

First, leave USB_FULL_INIT on for all non-bootloader builds; this is
needed for devices that don't have a USBSTACK (such as most hosted
targets and ones that provide USB<>ATA in hardware)

Then unwind another hack that is no longer needed now that USB_FULL_INIT
is not set in most bootloaders.

Change-Id: I00881ac76b2469e5cd7700bad2203c58ef1e09e7

firmware/usb.c

@@ -59,7 +59,7 @@
 #include "iap.h"
 #endif
 
-#if defined(HAVE_USBSTACK) && (!defined(BOOTLOADER) || defined(HAVE_BOOTLOADER_USB_MODE))
+#if (!defined(BOOTLOADER) || defined(HAVE_BOOTLOADER_USB_MODE))
 #define USB_FULL_INIT
 #endif
 
@@ -704,7 +704,6 @@ void usb_acknowledge(long id, intptr_t seqnum)
 {
     queue_post(&usb_queue, id, seqnum);
 }
-
 #else /* !USB_FULL_INIT */
 /* TODO:  All of this can go away once usb_core.c is no longer built
    with BOOTLOADER && !HAVE_USB_BOOTLOADER_MODE */
@@ -816,7 +815,7 @@ bool usb_inserted(void)
     return usb_state == USB_INSERTED || usb_state == USB_POWERED;
 }
 
-#if defined(HAVE_USBSTACK) && defined(USB_FULL_INIT)
+#if defined(USB_FULL_INIT)
 bool usb_exclusive_storage(void)
 {
     /* Storage isn't actually exclusive until slave mode has been entered */