Fix for fsl_upm

[Rusev]

patch is vs. 2.6.39, yet it applied to 3.1



Fix of UPM driver for Freescale PowerPC processors

If Freescale LBC driver fails to initialise itself from device tree,
then internal structure is freed only but not NULL-fied.
As result functions fsl_lbc_find() after checking the structure is not NULL are
trying to access device registers.

Signed-off-by: Alexandre Rusev <arusev@xxxxxxxxxxxxx> 
--- linux-2.6.39.old/arch/powerpc/sysdev/fsl_lbc.c	2011-10-27 03:17:28.000000000 +0400
+++ linux-2.6.39/arch/powerpc/sysdev/fsl_lbc.c	2011-10-27 05:06:44.000000000 +0400
@@ -322,6 +322,7 @@ static int __devinit fsl_lbc_ctrl_probe(
 err:
 	iounmap(fsl_lbc_ctrl_dev->regs);
 	kfree(fsl_lbc_ctrl_dev);
+	fsl_lbc_ctrl_dev = NULL;
 	return ret;
 }