clk: pxa: pxa3xx: fix CKEN register access

Clocks 0 to 31 are on CKENA, and not CKENB. The clock register names
were inadequately inverted. As a consequence, all clock operations were
happening on CKENB, because almost all but 2 clocks are on CKENA.

As the clocks were activated by the bootloader in the former tests, it
escaped the testing that the wrong clock gate was manipulated. The error
was revealed by changing the pxa3xx-nand driver to a module, where upon
unloading, the wrong clock was disabled in CKENB.

Fixes: 9bbb8a33 ("clk: pxa: add pxa3xx clock driver")
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>