This reverts commit a62230d8e886a766d1fb4d93dbc2b92275aa98c5.

What I believe is a bug in the Linux kernel (missing sfence.vma here
https://github.com/torvalds/linux/blob/master/arch/riscv/kernel/head.S#L123)
causes the kernel to fail to boot.

It's not necessary to match on the entire physical address of the PTE.
Instead, can match on the VPN subfields in TCAM fashion.  This reduces
the tag size from 35 bits to 19 for Sv39 with 38-bit physical addresses.

This allows MMIO loads to proceed at full throughput, rather than half.

TLSRAM: add support for integrated atomic ALU

* name fix