radv: remove unnecessary NULL checks in vkMapMemory()/vkUnmapMemory()

It's required to have a valid device memory handle and it would make
no sense to call these functions with a NULL pointer.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14287>

src/amd/vulkan/radv_device.c

@@ -5473,11 +5473,6 @@ radv_MapMemory(VkDevice _device, VkDeviceMemory _memory, VkDeviceSize offset, Vk
    RADV_FROM_HANDLE(radv_device, device, _device);
    RADV_FROM_HANDLE(radv_device_memory, mem, _memory);
 
-   if (mem == NULL) {
-      *ppData = NULL;
-      return VK_SUCCESS;
-   }
-
    if (mem->user_ptr)
       *ppData = mem->user_ptr;
    else
@@ -5497,9 +5492,6 @@ radv_UnmapMemory(VkDevice _device, VkDeviceMemory _memory)
    RADV_FROM_HANDLE(radv_device, device, _device);
    RADV_FROM_HANDLE(radv_device_memory, mem, _memory);
 
-   if (mem == NULL)
-      return;
-
    if (mem->user_ptr == NULL)
       device->ws->buffer_unmap(mem->bo);
 }