MAINTAINERS: update maintain status of FIRMWARE LOADER

Recently firmware loader code has been cleaned up much and
cache/uncache firmware mechanism is introduced, so later
drivers should apply the mechanism to solve the problem
of firmware lost during suspend/resume cycle.

For the sake of helping the related problems, I'd like to
volunteer to maintain the code and help on drivers' related
problem, so update the item.

Signed-off-by: Ming Lei <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

MAINTAINERS

···
 F:	tools/firewire/
 
 FIRMWARE LOADER (request_firmware)
-S:	Orphan
+M:	Ming Lei <[e-mail]>
+L:	[e-mail]
+S:	Maintained
 F:	Documentation/firmware_class/
 F:	drivers/base/firmware*.c
 F:	include/linux/firmware.h