[masm] Cleanup argument handling
[masm] Cleanup argument handling

Simplify the code for determining whether to push a function call parameter
onto the stack or into a register.

Change-Id: I3ab9230b8c0a3b2466c3000d89faf4fd79f927eb
Reviewed-by: Erik Verbruggen <5edfe905d082749f2ac3f4e6b42937f39f083771@digia.com>

mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative,matthewvogt/qtdeclarative,mgrunditz/qtdeclarative-2d,matthewvogt/qtdeclarative,matthewvogt/qtdeclarative,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative,qmlc/qtdeclarative,matthewvogt/qtdeclarative,matthewvogt/qtdeclarative,qmlc/qtdeclarative,mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative,matthewvogt/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative,matthewvogt/qtdeclarative,matthewvogt/qtdeclarative,qmlc/qtdeclarative