arm64: cachetype: fix definitions of ICACHEF_* flags

test_bit and set_bit take the bit number to operate on, rather than a
mask. This patch fixes the ICACHEF_* definitions so that they represent
the bit index in __icache_flags as opposed to the mask returned by the
BIT macro.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>