mmc: remove use of __devexit_p

CONFIG_HOTPLUG is going away as an option so __devexit_p is no longer
needed.

Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Chris Ball <cjb@laptop.org>
Cc: "Michał Mirosław" <mirq-linux@rere.qmqm.pl>
Cc: Jarkko Lavinen <jarkko.lavinen@nokia.com>
Cc: Venkatraman S <svenkatr@ti.com>
Cc: Ian Molton <ian@mnementh.co.uk>
Cc: Bruce Chang <brucechang@via.com.tw>
Cc: Harald Welte <HaraldWelte@viatech.com>
Cc: Pierre Ossman <pierre@ossman.eu>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>