aarch64: Expand maximum number of operands from 5 to 6

Given the introduction of the new Armv9.4-a `sysp' insn using the
following syntax:

	sysp #<op1>, <Cn>, <Cm>, #<op2>{, <Xt1>, <Xt2>}

and by extension the need to encode 6 assembly operands, extend
Binutils to handle instructions taking 6 operands, up from a previous
maximum of 5.

include/opcode/aarch64.h

@@ -1075,7 +1075,7 @@ enum err_type
 };
 
 /* Maximum number of operands an instruction can have.  */
-#define AARCH64_MAX_OPND_NUM 6
+#define AARCH64_MAX_OPND_NUM 7
 /* Maximum number of qualifier sequences an instruction can have.  */
 #define AARCH64_MAX_QLF_SEQ_NUM 10
 /* Operand qualifier typedef; optimized for the size.  */