ARM: OMAP2+: SmartReflex: add omap_sr_pdata definition

The omap_sr_pdata is not declared but is exported, so add a
define for it to fix the following warning:

arch/arm/mach-omap2/pdata-quirks.c:609:36: warning: symbol 'omap_sr_pdata' was not declared. Should it be static?

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>