sysutils/u-boot: Update to 2019.07

Remove one patch for RockChip RK3399 that was upstream.
Add a patch for storage api to remove SCSI. Allwinner A20 was converted
to DM_SCSI upstream and we don't have a good way to do what the api code
was doing (only had a brief look). This patch will probably be upstreamed
once I've found a better way. For now this means that you cannot boot from
SCSI drives using ubldr, using loader.efi will still work. Only Allwinner A20
boards are affected by this.