firmware: create firmware binaries during 'make modules'.

This means that we no longer need write access to the source tree while
doing 'make modules_install'.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/scripts/Makefile.fwinst b/scripts/Makefile.fwinst
index c972c0f..f63a663 100644
--- a/scripts/Makefile.fwinst
+++ b/scripts/Makefile.fwinst
@@ -17,14 +17,15 @@
 
 include scripts/Makefile.host
 
-mod-fw := $(addprefix $(INSTALL_FW_PATH)/,$(fw-shipped-m))
-
+mod-fw := $(fw-shipped-m)
 # If CONFIG_FIRMWARE_IN_KERNEL isn't set, then install the 
 # firmware for in-kernel drivers too.
 ifndef CONFIG_FIRMWARE_IN_KERNEL
-mod-fw += $(addprefix $(INSTALL_FW_PATH)/,$(fw-shipped-y))
+mod-fw += $(fw-shipped-y)
 endif
 
+installed-mod-fw := $(addprefix $(INSTALL_FW_PATH)/,$(mod-fw))
+
 installed-fw := $(addprefix $(INSTALL_FW_PATH)/,$(fw-shipped-all))
 installed-fw-dirs := $(sort $(dir $(installed-fw))) $(INSTALL_FW_PATH)/.
 
@@ -49,7 +50,8 @@
 .PHONY: $(PHONY)
 
 __fw_install: $(installed-fw)
-__fw_modinst: $(mod-fw)
+__fw_modinst: $(installed-mod-fw)
+__fw_modbuild: $(addprefix $(obj)/,$(mod-fw))
 
 FORCE: