Fix drivers/scsi/aic7xxx/Makefile for building a modular aic7xxx driver

Use the (well, one) standard way to build a multi-part module. 
Standard except for that we build aix7xxx_mod.o but then rename it
at modules_install time (just as it was before).

drivers/scsi/aic7xxx/Makefile

@@ -5,18 +5,20 @@
 O_TARGET := aic7xxx_drv.o
 MOD_TARGET = aic7xxx.o
 
+obj-$(CONFIG_SCSI_AIC7XXX)	+= aic7xxx_mod.o
+
 # Core files
-obj-$(CONFIG_SCSI_AIC7XXX)	+= aic7xxx.o aic7xxx_93cx6.o aic7770.o
+aix7xxx_mod-objs	+= aic7xxx.o aic7xxx_93cx6.o aic7770.o
 
 # Platform Specific Files
-obj-$(CONFIG_SCSI_AIC7XXX)	+= aic7xxx_linux.o aic7xxx_proc.o aic7770_linux.o
+aic7xxx_mod-objs	+= aic7xxx_linux.o aic7xxx_proc.o aic7770_linux.o
 
 # PCI Specific Files
 ifeq ($(CONFIG_PCI),y)
   # Core PCI files
-  obj-$(CONFIG_SCSI_AIC7XXX) += aic7xxx_pci.o
+  aic7xxx_mod-objs	+= aic7xxx_pci.o
   # Platform Specific PCI Files
-  obj-$(CONFIG_SCSI_AIC7XXX) += aic7xxx_linux_pci.o
+  aic7xxx_mod-objs	+= aic7xxx_linux_pci.o
 endif
 
 #EXTRA_CFLAGS += -g
@@ -30,3 +32,5 @@ endif
 
 aicasm/aicasm: aicasm/*.[chyl]
 	$(MAKE) -C aicasm
+
+aix7xxx_mod.o: aic7xxx_seq.h aic7xxx_reg.h