ARM: Introduce erratum workaround for 454179

ARM: Introduce erratum workaround for 454179

454179: Stale prediction may inhibit target address misprediction on
	next predicted taken branch
Impacts: Every Cortex-A8 processors with revision lower than r2p1
Work around:  Set IBE and disable branch size mispredict to 1

Also provide a hook for SoC specific handling to take place if needed.

Based on ARM errata Document revision 20.0 (13 Nov 2010)

Signed-off-by: Nishanth Menon <[email protected]>
Tested-by: Matt Porter <[email protected]>
Reviewed-by: Tom Rini <[email protected]>