tcg: Widen CPUTLBEntry comparators to 64-bits

This makes CPUTLBEntry agnostic to the address size of the guest.
When 32-bit addresses are in effect, we can simply read the low
32 bits of the 64-bit field.  Similarly when we need to update
the field for setting TLB_NOTDIRTY.

For TCG backends that could in theory be big-endian, but in
practice are not (arm, loongarch, riscv), use QEMU_BUILD_BUG_ON
to document and ensure this is not accidentally missed.

For s390x, which is always big-endian, use HOST_BIG_ENDIAN anyway,
to document the reason for the adjustment.

For sparc64 and ppc64, always perform a 64-bit load, and rely on
the following 32-bit comparison to ignore the high bits.

Rearrange mips and ppc if ladders for clarity.

Reviewed-by: Anton Johansson <anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

tcg/loongarch64/tcg-target.c.inc

@@ -875,6 +875,7 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext *s, HostAddress *h,
     tcg_out_opc_add_d(s, TCG_REG_TMP2, TCG_REG_TMP2, TCG_REG_TMP1);
 
     /* Load the tlb comparator and the addend.  */
+    QEMU_BUILD_BUG_ON(HOST_BIG_ENDIAN);
     tcg_out_ld(s, addr_type, TCG_REG_TMP0, TCG_REG_TMP2,
                is_ld ? offsetof(CPUTLBEntry, addr_read)
                      : offsetof(CPUTLBEntry, addr_write));