backlight: lp855x_bl: silence a compiler warning

Gcc 4.6.2 complains that "end" can be used without being initialized:

drivers/video/backlight/lp855x_bl.c: In function ‘lp855x_init_registers’:
drivers/video/backlight/lp855x_bl.c:78:32: warning: ‘end’ may be used uninitialized in this function [-Wuninitialized] drivers/video/backlight/lp855x_bl.c:67:12: note: ‘end’ was declared here

I've modified the function to return invalid if we don't recognize the id string.

index 8f628b8..5e8153d 100644
@@ -73,6 +73,8 @@ static int lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
 	} else if (strstr(id, "lp8556")) {
 		start = EPROM_START;
 		end = EPROM_END;
+	} else {
+		return 0;
 	}
 
 	return (addr >= start && addr <= end) ? 1 : 0;

DQo+IC0tLS0tT3JpZ2luYWwgTWVzc2FnZS0tLS0tDQo+IEZyb206IERhbiBDYXJwZW50ZXIgW21h aWx0bzpkYW4uY2FycGVudGVyQG9yYWNsZS5jb21dDQo+IFNlbnQ6IFdlZG5lc2RheSwgRmVicnVh cnkgMDEsIDIwMTIgMTE6MzkgUE0NCj4gVG86IFJpY2hhcmQgUHVyZGllOyBLaW1AZWxnb24ubW91 bnRhaW47IEtpbSwgTWlsbw0KPiBDYzogRmxvcmlhbiBUb2JpYXMgU2NoYW5kaW5hdDsgbGludXgt ZmJkZXZAdmdlci5rZXJuZWwub3JnOyBrZXJuZWwtDQo+IGphbml0b3JzQHZnZXIua2VybmVsLm9y Zw0KPiBTdWJqZWN0OiBbcGF0Y2hdIGJhY2tsaWdodDogbHA4NTV4X2JsOiBzaWxlbmNlIGEgY29t cGlsZXIgd2FybmluZw0KPiANCj4gR2NjIDQuNi4yIGNvbXBsYWlucyB0aGF0ICJlbmQiIGNhbiBi ZSB1c2VkIHdpdGhvdXQgYmVpbmcgaW5pdGlhbGl6ZWQ6DQo+IA0KPiBkcml2ZXJzL3ZpZGVvL2Jh Y2tsaWdodC9scDg1NXhfYmwuYzogSW4gZnVuY3Rpb24NCj4g4oCYbHA4NTV4X2luaXRfcmVnaXN0 ZXJz4oCZOg0KPiBkcml2ZXJzL3ZpZGVvL2JhY2tsaWdodC9scDg1NXhfYmwuYzo3ODozMjogd2Fy bmluZzog4oCYZW5k4oCZIG1heSBiZSB1c2VkDQo+IHVuaW5pdGlhbGl6ZWQgaW4gdGhpcyBmdW5j dGlvbiBbLVd1bmluaXRpYWxpemVkXQ0KPiBkcml2ZXJzL3ZpZGVvL2JhY2tsaWdodC9scDg1NXhf YmwuYzo2NzoxMjogbm90ZTog4oCYZW5k4oCZIHdhcyBkZWNsYXJlZA0KPiBoZXJlDQo+IA0KPiBJ J3ZlIG1vZGlmaWVkIHRoZSBmdW5jdGlvbiB0byByZXR1cm4gaW52YWxpZCBpZiB3ZSBkb24ndCBy ZWNvZ25pemUgdGhlDQo+IGlkIHN0cmluZy4NCj4gDQo+IFNpZ25lZC1vZmYtYnk6IERhbiBDYXJw ZW50ZXIgPGRhbi5jYXJwZW50ZXJAb3JhY2xlLmNvbT4NCg0KQWNrZWQtYnk6IE1pbG8oV29vZ3lv bSkgS2ltIDxtaWxvLmtpbUB0aS5jb20+DQoNClRoYW5rcyAhDQoNCkJlc3QgUmVnYXJkcywNCk1p bG8gLQ0KIA0KDQo