power: supply: pcf50633-charger: remove redundant variable charging_start

Variable charging_start is being set but is never read, it is therefore
redundant and can be removed. Cleans up sparse warning:

drivers/power/supply/pcf50633-charger.c:61:3: warning: Value stored to
'charging_start' is never read
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>

drivers/power/supply/pcf50633-charger.c

@@ -43,7 +43,6 @@ int pcf50633_mbc_usb_curlim_set(struct pcf50633 *pcf, int ma)
 	struct pcf50633_mbc *mbc = platform_get_drvdata(pcf->mbc_pdev);
 	int ret = 0;
 	u8 bits;
-	int charging_start = 1;
 	u8 mbcs2, chgmod;
 	unsigned int mbcc5;
 
@@ -58,7 +57,6 @@ int pcf50633_mbc_usb_curlim_set(struct pcf50633 *pcf, int ma)
 		ma = 100;
 	} else {
 		bits = PCF50633_MBCC7_USB_SUSPEND;
-		charging_start = 0;
 		ma = 0;
 	}