[ARM] xsc3: fix xsc3_l2_inv_range

[ARM] xsc3: fix xsc3_l2_inv_range

When 'start' and 'end' are less than a cacheline apart and 'start' is
unaligned we are done after cleaning and invalidating the first
cacheline.  So check for (start < end) which will not walk off into
invalid address ranges when (start > end).

This issue was caught by drivers/dma/dmatest.

2.6.27 is susceptible.

Cc: <[email protected]>
Cc: Haavard Skinnemoen <[email protected]>
Cc: Lothar WaÃ<9f>mann <[email protected]>
Cc: Lennert Buytenhek <[email protected]>
Cc: Eric Miao <[email protected]>
Signed-off-by: Dan Williams <[email protected]>