drm/amdgpu: Replace ternary operator with min() in 'amdgpu_iomem_write'

Fixes the following coccicheck:

drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c:2482:16-17: WARNING opportunity for min()

min() macro is defined in include/linux/minmax.h. It avoids multiple
evaluations of the arguments when non-constant and performs strict
type-checking.

Cc: Guchun Chen <guchun.chen@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c

@@ -2474,7 +2474,7 @@ static ssize_t amdgpu_iomem_write(struct file *f, const char __user *buf,
 		struct page *p;
 		void *ptr;
 
-		bytes = bytes < size ? bytes : size;
+		bytes = min(bytes, size);
 
 		addr = dom ? iommu_iova_to_phys(dom, addr) : addr;