aarch64: Replace incorrect comment

The comment explaining the placement of the cfinv entry before the
generic msr entry in the opcode table was incorrect.  The issue is
unrelated to the all ones bitmask for cfinv, and is actually due the
large number of architectural aliases of the msr instruction.

Author: Alice Carlotti

opcodes/aarch64-tbl.h

@@ -4642,14 +4642,14 @@ const struct aarch64_opcode aarch64_opcode_table[] =
   PREDRES_INSN ("cpp", 0xd50b73e0, 0xffffffe0, ic_system, OP2 (SYSREG_SR, Rt), QL_SRC_X, F_ALIAS),
   PREDRES2_INSN ("cosp", 0xd50b73c0, 0xffffffe0, ic_system, OP2 (SYSREG_SR, Rt), QL_SRC_X, F_ALIAS),
   BRBE_INSN ("brb", 0xd5097280, 0xffffffc0, OP2 (BRBOP, Rt_IN_SYS_ALIASES), QL_IMM_NIL_NIL, F_ALIAS | F_OPD1_OPT | F_DEFAULT (0x1F)),
-  /* Armv8.4-a flag setting instruction, However this encoding has an encoding clash with the msr
-     below it.  Usually we can resolve this by setting an alias condition on the flags, however that
-     depends on the disassembly masks to be able to quickly find the alias.  The problem is the
-     cfinv instruction has no arguments, so all bits are set in the mask.  Which means it will
-     potentially alias with too many instructions and so the tree can't be constructed.   As a work
-     around we just place cfinv before msr.  This means the order between these two shouldn't be
-     changed.  */
   FLAGM_INSN ("cfinv",  0xd500401f, 0xffffffff, ic_system, OP0 (), {}, 0),
+  /* This msr entry has a lot of aliases, and some of these (such as "hint")
+     have their own (recursive) aliases.  We currently use a flat alias
+     structure, so to avoid creating an excessively long list of aliases for
+     the entire msr space we instead handle the top level of disambiguation
+     outside the alias infrastructure.  This requires that all of the top-level
+     aliases of msr must appear earlier in the opcode table, since normal
+     (non-alias) disassembly is done on a "first match" basis.  */
   CORE_INSN ("msr", 0xd5000000, 0xffe00000, ic_system, 0, OP2 (SYSREG, Rt), QL_SRC_X, F_SYS_WRITE),
   CORE_INSN ("sysl",0xd5280000, 0xfff80000, ic_system, 0, OP5 (Rt, UIMM3_OP1, CRn, CRm, UIMM3_OP2), QL_SYSL, 0),
   CORE_INSN ("mrs", 0xd5200000, 0xffe00000, ic_system, 0, OP2 (Rt, SYSREG), QL_DST_X, F_SYS_READ),