clang-format: Avoid breaking after the opening paren of function definitions

This depends on https://reviews.llvm.org/D90246 to have any effect, but once
that has landed clang-format will no longer format code like this:

```
int
myfunction(
    int param1, int param2, int param2)
{
   ...
}
```

and instead create the following:

```
int
myfunction(int param1, int param2,
    int param2)
{
   ...
}
```

Reviewed By:	emaste, cem
Differential Revision: https://reviews.freebsd.org/D26978

.clang-format

@@ -8,6 +8,7 @@ AlignConsecutiveDeclarations: false
 AlignEscapedNewlines: Left
 AlignOperands: false
 AlignTrailingComments: true
+AllowAllArgumentsOnNextLine: false
 AllowAllParametersOfDeclarationOnNextLine: false
 AllowShortBlocksOnASingleLine: Never
 AllowShortCaseLabelsOnASingleLine: false
@@ -24,7 +25,20 @@ BreakBeforeBraces: WebKit
 BreakBeforeTernaryOperators: false
 # TODO: BreakStringLiterals can cause very strange formatting so turn it off?
 BreakStringLiterals: false
-PenaltyBreakBeforeFirstCallParameter: 1000
+# Prefer:
+# some_var = function(arg1,
+#    arg2)
+# over:
+# some_var =
+#     function(arg1, arg2)
+PenaltyBreakAssignment: 100
+# Prefer:
+# some_long_function(arg1, arg2
+#     arg3)
+# over:
+# some_long_function(
+#     arg1, arg2, arg3)
+PenaltyBreakBeforeFirstCallParameter: 100
 CompactNamespaces: true
 DerivePointerAlignment: false
 DisableFormat: false