examples:images: Fix linker error
examples:images: Fix linker error

Explicitly link with libm to avoid linker errors.

Signed-off-by: Ola Jeppsson <793f970c52ded1276b9264c742f19d1888cbaf73@adapteva.com>

RafaelRMA/pal,mateunho/pal,RafaelRMA/pal,mateunho/pal,RafaelRMA/pal,8l/pal,olajep/pal,aolofsson/pal,parallella/pal,8l/pal,eliteraspberries/pal,debug-de-su-ka/pal,aolofsson/pal,eliteraspberries/pal,eliteraspberries/pal,olajep/pal,olajep/pal,parallella/pal,debug-de-su-ka/pal,Adamszk/pal3,aolofsson/pal,mateunho/pal,Adamszk/pal3,eliteraspberries/pal,RafaelRMA/pal,olajep/pal,Adamszk/pal3,8l/pal,mateunho/pal,parallella/pal,Adamszk/pal3,debug-de-su-ka/pal,aolofsson/pal,8l/pal,parallella/pal,debug-de-su-ka/pal,debug-de-su-ka/pal,mateunho/pal,eliteraspberries/pal,parallella/pal