mmc: register mmci-omap-hs using platform_driver_probe

omap_mmc_probe lives in .init.text, so using platform_driver_register to
register it is wrong because binding a device after the init memory is
discarded (e.g.  via sysfs) results in an oops.

As requested by David Brownell platform_driver_probe is used instead of
moving the probe function to .devinit.text as proposed initially.  This
saves some memory, but devices registered after the driver is probed are
not bound (probably there are none) and binding via sysfs isn't possible.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Jean Pihet <jpihet@mvista.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Pierre Ossman <drzeus@drzeus.cx>
Cc: Andy Lowe <alowe@mvista.com>
Cc: Adrian Hunter <ext-adrian.hunter@nokia.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Madhusudhan Chikkature<madhu.cr@ti.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Matt Fleming <matt@console-pimps.org>
Cc: Ian Molton <ian@mnementh.co.uk>
Cc: "Roberto A. Foglietta" <roberto.foglietta@gmail.com>
Cc: Philip Langdale <philipl@overt.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>