drm/nouveau: switch over to vmemdup_user()

[Atul Raut]

Use vmemdup_user() rather than duplicating its implementation.

This patch fixes the following Coccinelle warning:
./drivers/gpu/drm/nouveau/nouveau_gem.c:630:7-15: WARNING opportunity for 
vmemdup_user

Signed-off-by: Atul Raut <rauji.r...@gmail.com>
---
 drivers/gpu/drm/nouveau/nouveau_gem.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c 
b/drivers/gpu/drm/nouveau/nouveau_gem.c
index ab9062e50977..a244b39df213 100644
--- a/drivers/gpu/drm/nouveau/nouveau_gem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
@@ -627,15 +627,10 @@ u_memcpya(uint64_t user, unsigned nmemb, unsigned size)
 
        size *= nmemb;
 
-       mem = kvmalloc(size, GFP_KERNEL);
-       if (!mem)
+       mem = vmemdup_user(userptr, size);
+       if (IS_ERR(mem))
                return ERR_PTR(-ENOMEM);
 
-       if (copy_from_user(mem, userptr, size)) {
-               u_free(mem);
-               return ERR_PTR(-EFAULT);
-       }
-
        return mem;
 }
 
-- 
2.34.1