[PATCH] Add symbol type files (*.symtypes) to .gitignore

The kernel build system supports making symbol type files (*.symtypes) from C
source files.  Add these files to .gitignore.

Signed-off-by: Josh Triplett <josh@freedesktop.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>