ihex: add ihex2fw tool for converting HEX files into firmware images

Not the straight conversion to binary which objcopy can do for us, but
actually representing each record with its original {addr, length},
because some drivers need that information preserved.

Fix up 'firmware_install' to be able to build $(hostprogs-y) too.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

scripts/Makefile.fwinst

@@ -6,6 +6,7 @@
 # ==========================================================================
 
 INSTALL := install
+src := $(obj)
 
 # For modules_install installing firmware, we want to see .config
 # But for firmware_install, we don't care, but don't want to require it.
@@ -41,5 +42,4 @@ $(installed-fw): $(INSTALL_FW_PATH)/%: $(obj)/% | $(INSTALL_FW_PATH)/$$(dir %)/
 __fw_install: $(installed-fw)
 __fw_modinst: $(mod-fw)
 
-
 FORCE: