arm: Add v7_invalidate_l1 to cache-v7.S

arm: Add v7_invalidate_l1 to cache-v7.S

mach-socfpga is another platform that needs to use
v7_invalidate_l1 to bringup additional cores. There was a comment that
the ideal place for v7_invalidate_l1 should be in arm/mm/cache-v7.S

Signed-off-by: Dinh Nguyen <[email protected]>
Acked-by: Simon Horman <[email protected]>
Acked-by: Stephen Warren <[email protected]>
Reviewed-by: Pavel Machek <[email protected]>
Reviewed-by: Santosh Shilimkar <[email protected]>
Tested-by: Pavel Machek <[email protected]>
Tested-by: Stephen Warren <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Russell King <[email protected]>
Cc: Olof Johansson <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Rob Herring <[email protected]>
Cc: Sascha Hauer <[email protected]>
Cc: Magnus Damm <[email protected]>
Signed-off-by: Olof Johansson <[email protected]>