driver/char/generic_nvram: fix banner

The generic nvram driver announces itself as
	'Macintosh non-volatile memory driver'
instead of 'Generic non-volatile memory driver'.  Fix that.

Signed-off-by: Philippe De Muyter <phdm@macqel.be>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>