crypto: arm/sha256-neon - avoid ADRL pseudo instruction

The ADRL pseudo instruction is not an architectural construct, but a
convenience macro that was supported by the ARM proprietary assembler
and adopted by binutils GAS as well, but only when assembling in 32-bit
ARM mode. Therefore, it can only be used in assembler code that is known
to assemble in ARM mode only, but as it turns out, the Clang assembler
does not implement ADRL at all, and so it is better to get rid of it
entirely.

So replace the ADRL instruction with a ADR instruction that refers to
a nearer symbol, and apply the delta explicitly using an additional
instruction.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>