rsx: Apply Clang-Tidy fix "readability-simplify-subscript-expr"

rpcs3/Emu/RSX/GL/GLFragmentProgram.cpp

@@ -127,7 +127,7 @@ void GLFragmentDecompilerThread::insertConstants(std::stringstream & OS)
 		for (const ParamItem& PI : PT.items)
 		{
 			std::string samplerType = PT.type;
-			int index = atoi(&PI.name.data()[3]);
+			int index = atoi(&PI.name[3]);
 
 			const auto mask = (1 << index);
 

rpcs3/Emu/RSX/VK/VKFragmentProgram.cpp

@@ -126,7 +126,7 @@ void VKFragmentDecompilerThread::insertConstants(std::stringstream & OS)
 		for (const ParamItem& PI : PT.items)
 		{
 			std::string samplerType = PT.type;
-			int index = atoi(&PI.name.data()[3]);
+			int index = atoi(&PI.name[3]);
 
 			const auto mask = (1 << index);