OMAP3: PM: fix scratchpad memory accesses for off-mode

Commit 914bab936fe0388a529079679e2f137aa4ff548d (OMAP: mach-omap2: Fix
incorrect assignment warnings) changed a pointer from 'u32 *' to
'void *' without also fixing up the pointer arithmetic.

Fix the scratchpad offsets so they are byte offsets instead of
word offsets and thus work correctly with a void pointer base.

Special thanks to Jean Pihet for taking the time track down this
problem and propose an initial solution.

Tested with off-idle and off-suspend on 36xx/Zoom3 and 34xx/omap3evm.

Cc: Manjunath Kondaiah G <manjugk@ti.com>
Reported-by: Jean Pihet <jean.pihet@newoldbits.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Tested-by: Jean Pihet <jean.pihet@newoldbits.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>