hw/intc: Add .impl.[min|max]_access_size declaration in RISC-V ACLINT

If device's MemoryRegion doesn't have .impl.[min|max]_access_size
declaration, the default access_size_min would be 1 byte and
access_size_max would be 4 bytes (see: softmmu/memory.c).
This will cause a 64-bit memory access to ACLINT to be splitted into
two 32-bit memory accesses.

Signed-off-by: Frank Chang <frank.chang@sifive.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Jim Shu <jim.shu@sifive.com>
Message-Id: <20220420080901.14655-2-frank.chang@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

hw/intc/riscv_aclint.c

@@ -208,6 +208,10 @@ static const MemoryRegionOps riscv_aclint_mtimer_ops = {
     .valid = {
         .min_access_size = 4,
         .max_access_size = 8
+    },
+    .impl = {
+        .min_access_size = 4,
+        .max_access_size = 8,
     }
 };