ARM: OMAP3+: SmartReflex: class drivers should use struct omap_sr *

Convert SmartReflex "class" functions to take a struct omap_sr *, rather than
a struct voltagedomain *.  SmartReflex code should be driver code and not
tightly coupled to OMAP subarchitecture-specific structures.

Based on Paul's original code for the SmartReflex driver conversion.

Signed-off-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: J Keerthy <j-keerthy@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>