[U-Boot] efi_loader: search all possible disk partitions

[Alexander Graf]

> When searching for partitions don't stop if a partition is not present
> for a given partition number as there may be valid partitions after.
> 
> Search for up to MAX_SEARCH_PARTITIONS matching the other callers of
> part_get_info().
> 
> This allows OpenBSD to boot via the efi_loader on rpi_3 again after
> changes made after U-Boot 2017.09.  With MBR partitioning OpenBSD will
> by default use the fourth partition for the 0xA6 (OpenBSD) partition.
> 
> Signed-off-by: Jonathan Gray <jsg at jsg.id.au>

Thanks, applied to efi-next

Alex