arm: Kconfig: Disable CONFIG_OABI_COMPAT feature on SMP targets

When this option is enabled to support Old ABI, it introduces
a race condition in swap-out code on SMP, such that
instruction is available to the instruction stream (SWI
instruction) but not the data stream.

CPU0		CPU1
clears pte
		executes instruction from page,
		already has I-TLB but no D-TLB entry,
		takes SWI exception
		tries to load instruction, data abort
tlb flush

Therefore, disable this feature on SMP targets.

Change-Id: I4cc4e6924cfcffad391fe2e68d5aa62eee613b0e
Signed-off-by: Jay Chokshi <jchokshi@codeaurora.org>