detect/byte-math: Support multiplication operator

Issue: 6070

This commit adds support for the multiplication operator to byte-math.
The regex for parsing the keyword options was missing the `*` character.

src/detect-bytemath.c

@@ -76,7 +76,7 @@
     "^"                                                                                            \
     "\\s*(bytes)\\s*(\\d+)\\s*"                                                                    \
     ",\\s*(offset)\\s*([-]?\\d+)\\s*"                                                              \
-    ",\\s*(oper)\\s*([-+\\/]{1}|<<|>>)\\s*"                                                        \
+    ",\\s*(oper)\\s*([-+\\/\\*]{1}|<<|>>)\\s*"                                                     \
     ",\\s*(rvalue)\\s*(\\w+)\\s*"                                                                  \
     ",\\s*(result)\\s*(\\w+)\\s*"                                                                  \
     "(?:,\\s*(relative)\\s*)?"                                                                     \