Without this tag, we get a build warning:

WARNING: modpost: missing MODULE_LICENSE() in arch/arm/common/bL_switcher_dummy_if.o

For completeness, I'm also adding author and description fields.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>