Add .gitignore file

Allows 'git status' command to better show untracked files which one may be
interested in.

Signed-off-by: Russ Meyerriecks <rmeyerriecks@digium.com>
Acked-by: Shaun Ruffell <sruffell@digium.com>
Acked-by: Tzafrir Cohen <tzafrir.cohen@xorcom.com>
(cherry picked from commit d889fb39d3)

.gitignore

@@ -0,0 +1,40 @@
+# Files that are generated as part of the build process which we do not want git
+# to track.
+
+*.[oa]
+*.mod
+*.mod.[oc]
+*.ko
+*.cmd
+*.order
+*.tar.gz
+tags
+cscope.*
+*.symvers
+*.markers
+.*.o.d
+
+modules.order
+Module.markers
+build_tools/checkpatch.pl
+drivers/dahdi/xpp/*.verified
+drivers/dahdi/.tmp_versions/
+drivers/dahdi/Module.symvers
+drivers/dahdi/makefw
+drivers/dahdi/radfw.h
+drivers/dahdi/tor2fw.h
+drivers/dahdi/xpp/init_fxo_modes
+drivers/dahdi/xpp/print_fxo_modes
+drivers/dahdi/xpp/xpp_version.h
+include/dahdi/version.h
+drivers/dahdi/vpmadt032_loader/vpmadt032_loader.h
+drivers/dahdi/vpmadt032_loader/vpmadt032_x86_32.o_shipped
+drivers/dahdi/vpmadt032_loader/vpmadt032_x86_64.o_shipped
+drivers/dahdi/firmware/dahdi-fw-hx8.bin
+drivers/dahdi/firmware/dahdi-fw-oct6114-064.bin
+drivers/dahdi/firmware/dahdi-fw-oct6114-128.bin
+drivers/dahdi/firmware/dahdi-fw-oct6114-256.bin
+drivers/dahdi/firmware/dahdi-fw-tc400m.bin
+drivers/dahdi/firmware/dahdi-fw-te820.bin
+drivers/dahdi/firmware/dahdi-fw-vpmoct032.bin
+drivers/dahdi/firmware/make_firmware_object