anv: release memory allocated by glsl types during spirv_to_nir

anv: release memory allocated by glsl types during spirv_to_nir

Fixes leaks for each glsl_type generated:

  ==32470== 384 bytes in 3 blocks are possibly lost in loss record 18 of 18
  ==32470==    at 0x483880B: malloc (vg_replace_malloc.c:309)
  ==32470==    by 0x4C43F4A: ralloc_size (ralloc.c:119)
  ==32470==    by 0x4C44014: rzalloc_size (ralloc.c:151)
  ==32470==    by 0x4C44258: rzalloc_array_size (ralloc.c:215)
  ==32470==    by 0x4D38957: glsl_type::glsl_type(glsl_struct_field const*, unsigned int, char const*) (glsl_types.cpp:114)
  ==32470==    by 0x4D3BEED: glsl_type::get_struct_instance(glsl_struct_field const*, unsigned int, char const*) (glsl_types.cpp:1146)
  ==32470==    by 0x4D42ECC: glsl_struct_type (nir_types.cpp:501)
  ==32470==    by 0x4CDB5A1: vtn_handle_type (spirv_to_nir.c:1269)
  ==32470==    by 0x4CE53DD: vtn_handle_variable_or_type_instruction (spirv_to_nir.c:4018)
  ==32470==    by 0x4CD8CFF: vtn_foreach_instruction (spirv_to_nir.c:365)
  ==32470==    by 0x4CE5E6B: spirv_to_nir (spirv_to_nir.c:4490)
  ==32470==    by 0x497AF10: anv_shader_compile_to_nir (anv_pipeline.c:173)

v2: move release call to vkDestroyInstance

Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Cc: mesa-stable@lists.freedesktop.org
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>