usb gadget: link fixes for storage gadget

Change how the file storage gadget driver builds:  don't
use separate compilation, since it works poorly when key
parts are library code (with init sections etc).  Instead
be as close as we can to "gcc --combine ...".
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/usb/gadget/Makefile

@@ -29,8 +29,7 @@ g_ether-objs			:= ether.o u_ether.o f_subset.o f_ecm.o $(C_UTILS)
 g_serial-objs			:= serial.o
 g_midi-objs			:= gmidi.o
 gadgetfs-objs			:= inode.o
-g_file_storage-objs		:= file_storage.o usbstring.o config.o \
-					epautoconf.o
+g_file_storage-objs		:= file_storage.o
 g_printer-objs			:= printer.o
 g_cdc-objs			:= cdc2.o u_ether.o f_ecm.o \
 					u_serial.o f_acm.o $(C_UTILS)

drivers/usb/gadget/file_storage.c

@@ -245,6 +245,18 @@
 #include "gadget_chips.h"
 
 
+
+/*
+ * Kbuild is not very cooperative with respect to linking separately
+ * compiled library objects into one module.  So for now we won't use
+ * separate compilation ... ensuring init/exit sections work to shrink
+ * the runtime footprint, and giving us at least some parts of what
+ * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
+ */
+#include "usbstring.c"
+#include "config.c"
+#include "epautoconf.c"
+
 /*-------------------------------------------------------------------------*/
 
 #define DRIVER_DESC		"File-backed Storage Gadget"