drivers/mmc/host: use ERR_CAST

Use ERR_CAST(x) rather than ERR_PTR(PTR_ERR(x)).  The former makes more
clear what is the purpose of the operation, which otherwise looks like a
no-op.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
type T;
T x;
identifier f;
@@

T f (...) { <+...
- ERR_PTR(PTR_ERR(x))
+ x
 ...+> }

@@
expression x;
@@

- ERR_PTR(PTR_ERR(x))
+ ERR_CAST(x)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/mmc/host/sdhci-pci.c

@@ -628,7 +628,7 @@ static struct sdhci_pci_slot * __devinit sdhci_pci_probe_slot(
 	host = sdhci_alloc_host(&pdev->dev, sizeof(struct sdhci_pci_slot));
 	if (IS_ERR(host)) {
 		dev_err(&pdev->dev, "cannot allocate host\n");
-		return ERR_PTR(PTR_ERR(host));
+		return ERR_CAST(host);
 	}
 
 	slot = sdhci_priv(host);