update .gitignore

Ignore accidentally tracking xbboot build products.  Do track
Makefiles that are not automatically generated.  Fixing this makes
debian/clean.sh work again.

Mistakenly ignored files were detected by

	git ls-files -i --exclude-standard

and un-ignored build products by

	git ls-files -o --exclude-standard

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>

xbboot/.gitignore

@@ -1,11 +1,22 @@
-m4
-autom4te.cache
-config.h
-config.h.in
-config.log
-config.status
-Makefile
+/aclocal.m4
+/config.h
+/config.h.in
+/config.log
+/config.status
+/configure
+/stamp-h1
+/m4/
+/autom4te.cache/
+
 Makefile.in
-configure
-stamp-h1
-aclocal.m4
+
+/Makefile
+/host-app/Makefile
+
+*.lst
+*.o
+*.bin
+*.dump
+*.elf
+*.map
+*.sym

xbboot/target-stage1/.gitignore

@@ -1,8 +0,0 @@
-System.map
-head.o
-stage1.o
-stage1.bin
-stage1.dump
-stage1.elf
-stage1.map
-serial.o