[AArch64][SVE 02/32] Avoid hard-coded limit in indented_print

[AArch64][SVE 02/32] Avoid hard-coded limit in indented_print

The maximum indentation needed by aarch64-gen.c grows as more
instructions are added to aarch64-tbl.h.  Rather than having to
increase the indentation limit to a higher value, it seemed better
to replace it with "%*s".

opcodes/
	* aarch64-gen.c (indented_print): Avoid hard-coded indentation limit.