vulkan: fixed RDNA2 subgroup map

Author: daniandtheweb

ggml/src/ggml-vulkan/ggml-vulkan.cpp

@@ -1530,7 +1530,6 @@ static const std::unordered_map<std::string, uint32_t> rdna1_pipelines = {
 // Pipeline configuration for RDNA2 GPUs.
 static const std::unordered_map<std::string, uint32_t> rdna2_pipelines = {
     {"soft_max", 64}, {"im2col", 64},
-    {"argmax", 64},
 };
 
 static constexpr uint32_t RDNA_DEFAULT_SUBGROUP_SIZE = 32;