dtoc: Avoid very long lines in output

Large arrays can result in lines with hundreds or thousands of characters
which is not very editor-friendly. To avoid this, addjust the tool to
group values 8 per line.

Signed-off-by: Simon Glass <sjg@chromium.org>
Tested-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/tools/dtoc/test_dtoc.py b/tools/dtoc/test_dtoc.py
index 8b95c41..5040f23 100644
--- a/tools/dtoc/test_dtoc.py
+++ b/tools/dtoc/test_dtoc.py
@@ -146,7 +146,8 @@
 \t.bytearray\t\t= {0x6, 0x0, 0x0},
 \t.byteval\t\t= 0x5,
 \t.intval\t\t\t= 0x1,
-\t.longbytearray\t\t= {0x9, 0xa, 0xb, 0xc, 0xd, 0xe, 0xf, 0x10, 0x11},
+\t.longbytearray\t\t= {0x9, 0xa, 0xb, 0xc, 0xd, 0xe, 0xf, 0x10,
+\t\t0x11},
 \t.stringval\t\t= "message",
 \t.boolval\t\t= true,
 \t.intarray\t\t= {0x2, 0x3, 0x4, 0x0},
@@ -162,7 +163,8 @@
 \t.bytearray\t\t= {0x1, 0x23, 0x34},
 \t.byteval\t\t= 0x8,
 \t.intval\t\t\t= 0x3,
-\t.longbytearray\t\t= {0x9, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
+\t.longbytearray\t\t= {0x9, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+\t\t0x0},
 \t.stringval\t\t= "message2",
 \t.intarray\t\t= {0x5, 0x0, 0x0, 0x0},
 \t.stringarray\t\t= {"another", "multi-word", "message"},