x86/platform/pmc_atom: Fix warning when CONFIG_DEBUG_FS=n

When compiling with CONFIG_DEBUG_FS=n, GCC emits an unused
variable warning for pmc_atom.c because "ret" is used only
within the CONFIG_DEBUG_FS block.

This patch adds a dummy #ifdef for pmc_dbgfs_register() when
CONFIG_DEBUG_FS=n to simplify the code and remove the warning.

Signed-off-by: Martin Kelly <martkell@amazon.com>
Acked-by: "Li, Aubrey" <aubrey.li@linux.intel.com>
Cc: vishwesh.m.rudramuni@intel.com
Link: http://lkml.kernel.org/r/1410963476-8360-1-git-send-email-martin@martingkelly.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/pmc_atom.c

@@ -235,6 +235,11 @@ err:
 	pmc_dbgfs_unregister(pmc);
 	return -ENODEV;
 }
+#else
+static int pmc_dbgfs_register(struct pmc_dev *pmc, struct pci_dev *pdev)
+{
+	return 0;
+}
 #endif /* CONFIG_DEBUG_FS */
 
 static int pmc_setup_dev(struct pci_dev *pdev)
@@ -262,14 +267,12 @@ static int pmc_setup_dev(struct pci_dev *pdev)
 	/* PMC hardware registers setup */
 	pmc_hw_reg_setup(pmc);
 
-#ifdef CONFIG_DEBUG_FS
 	ret = pmc_dbgfs_register(pmc, pdev);
 	if (ret) {
 		iounmap(pmc->regmap);
-		return ret;
 	}
-#endif /* CONFIG_DEBUG_FS */
-	return 0;
+
+	return ret;
 }
 
 /*