[RFC V3] arm/arm64:add CONFIG_HAVE_ARCH_BITREVERSE to support rbit instruction

[Wang, Yalin]

> From: Will Deacon [mailto:will.deacon at arm.com]
> Yup, sorry, I didn't realise this patch covered both architectures. It
> would probably be a good idea to split it into 3 parts: a core part, then
> the two architectural bits.
> 
> Will

Ok ,
I will split the patch into three parts,
And send again .

Thanks