Fix WAVE loader format chunk read length in example code.
Fix WAVE loader format chunk read length in example code.

Thanks to Carolyn Wales! cswales . gmail com.

kevleyski/DirectFB-1,deniskropp/DirectFB,deniskropp/DirectFB,lancebaiyouview/DirectFB,djbclark/directfb-core-DirectFB,mtsekm/test,dfbdok/DirectFB1,Distrotech/DirectFB,jcdubois/DirectFB,Distrotech/DirectFB,djbclark/directfb-core-DirectFB,kaostao/directfb,sklnet/DirectFB,djbclark/directfb-core-DirectFB,mtsekm/test,kaostao/directfb,DirectFB/directfb,kaostao/directfb,kevleyski/DirectFB-1,kevleyski/directfb,sklnet/DirectFB,kevleyski/directfb,kevleyski/DirectFB-1,lancebaiyouview/DirectFB,kevleyski/directfb,mtsekm/test,lancebaiyouview/DirectFB,jcdubois/DirectFB,sklnet/DirectFB,DirectFB/directfb,sklnet/DirectFB,deniskropp/DirectFB,djbclark/directfb-core-DirectFB,dfbdok/DirectFB1,dfbdok/DirectFB1,Distrotech/DirectFB,DirectFB/directfb,jcdubois/DirectFB,deniskropp/DirectFB,lancebaiyouview/DirectFB,kevleyski/DirectFB-1,kevleyski/directfb