Fixes the following checkpatch errors:

ERROR: do not use assignment in if condition

Signed-off-by: Ran Sun <sunran001@208suo.com>
---
  drivers/gpu/drm/nouveau/nvkm/subdev/clk/mcp77.c | 3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/clk/mcp77.c 
b/drivers/gpu/drm/nouveau/nvkm/subdev/clk/mcp77.c
index f85d6a08c61a..77465bfa71ea 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/clk/mcp77.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/clk/mcp77.c
@@ -414,7 +414,8 @@ mcp77_clk_new(struct nvkm_device *device, enum 
nvkm_subdev_type type, int inst,
  {
      struct mcp77_clk *clk;

-    if (!(clk = kzalloc(sizeof(*clk), GFP_KERNEL)))
+    clk = kzalloc(sizeof(*clk), GFP_KERNEL);
+    if (!clk)
          return -ENOMEM;
      *pclk = &clk->base;