When configured as a lodable module, this driver produces
a build time warning:

ERROR: modpost: missing MODULE_LICENSE() in drivers/clk/clk-ep93xx.o

All all three tags for license, author and description based
on the header.
Acked-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>