vulkan: fix warnings (llama/13626)

* small fixes

* remove ifdef

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

@@ -4513,6 +4513,8 @@ static vk_pipeline ggml_vk_guess_matmul_pipeline(ggml_backend_vk_context * ctx,
         return aligned ? mmp->a_m : mmp->m;
     }
     return aligned ? mmp->a_l : mmp->l;
+
+    GGML_UNUSED(src1_type);
 }
 
 static uint32_t ggml_vk_guess_matmul_pipeline_align(ggml_backend_vk_context * ctx, vk_matmul_pipeline& mmp, int m, int n, ggml_type src0_type, ggml_type src1_type) {

ggml/src/ggml-vulkan/vulkan-shaders/dequant_iq1_m.comp

@@ -1,6 +1,6 @@
 #version 450
 
-#extension GL_EXT_shader_explicit_arithmetic_types_float16 : require
+#extension GL_EXT_shader_explicit_arithmetic_types_int16 : require
 
 #include "dequant_head.comp"
 

ggml/src/ggml-vulkan/vulkan-shaders/mul_mm.comp

@@ -7,7 +7,7 @@
 #extension GL_EXT_shader_explicit_arithmetic_types_float16 : require
 #endif
 #if defined(DATA_A_IQ1_M)
-#extension GL_EXT_shader_explicit_arithmetic_types_float16 : require
+#extension GL_EXT_shader_explicit_arithmetic_types_int16 : require
 #endif
 
 #if defined(DATA_A_BF16) && defined(COOPMAT)