hwmon: (fam15h_power) Correct sign extension of running_avg_capture

Wrong bit was used for sign extension which caused wrong end results.
Thanks to Andre for spotting this bug.
Reported-by: Andre Przywara <andre.przywara@amd.com>
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: stable@vger.kernel.org

drivers/hwmon/fam15h_power.c

@@ -60,7 +60,7 @@ static ssize_t show_power(struct device *dev,
 	pci_bus_read_config_dword(f4->bus, PCI_DEVFN(PCI_SLOT(f4->devfn), 5),
 				  REG_TDP_RUNNING_AVERAGE, &val);
 	running_avg_capture = (val >> 4) & 0x3fffff;
-	running_avg_capture = sign_extend32(running_avg_capture, 22);
+	running_avg_capture = sign_extend32(running_avg_capture, 21);
 	running_avg_range = val & 0xf;
 
 	pci_bus_read_config_dword(f4->bus, PCI_DEVFN(PCI_SLOT(f4->devfn), 5),