Replace the min size rtx with GEN_INT (min_size)

commit cbc56384029c9224280b0a1018fb9502797f243d
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri Jun 26 08:43:20 2026 +0800

    determine_block_size: Set len_rtx to min size if min size == max size

added

+    gcc_assert (min_size != max_size
+           || rtx_equal_p (ops[2].value, ops[6].value));

But the number of operands isn't fixed and may be less than 7.  Replace
the min size rtx with GEN_INT (min_size) to support different numbers of
operands.

	PR middle-end/125977
	* expr.cc (emit_block_move_via_pattern): Replace ops[6].value
	in assert with GEN_INT (min_size).

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>