OMAP3630: PM: Disable L2 cache while invalidating L2 cache

OMAP3630: PM: Disable L2 cache while invalidating L2 cache

While coming out of MPU OSWR/OFF states, L2 controller is reseted.
The reset behavior is implementation specific as per ARMv7 TRM and
hence $L2 needs to be invalidated before it's use. Since the
AUXCTRL register is also reconfigured, disable L2 cache before
invalidating it and re-enables it afterwards. This is as per
Cortex-A8 ARM documentation.
Currently this is identified as being needed on OMAP3630 as the
disable/enable is done from "public side" while, on OMAP3430, this
is done in the "secure side".

Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Tony Lindgren <tony@atomide.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
[nm@ti.com: ported to 2.6.37-rc2, added hooks to enable the logic only on 3630]
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Eduardo Valentin <eduardo.valentin@nokia.com>
Signed-off-by: Peter 'p2' De Schrijver <peter.de-schrijver@nokia.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>