board/orangepi/orangepi-pc-plus: fix build after genimage update

board/orangepi/orangepi-pc-plus: fix build after genimage update

ERROR: hdimage(sdcard.img): part boot: 'partition-type' is only valid for mbr and hybrid partition-table-type

To fix the first genimage error report, change 'partition-type' entries
to the appropriate 'partition-type-uuid'. Then genimage starts to
complain about overlaps:

ERROR: hdimage(sdcard.img): partition [GPT array] (offset 0x100000, size 0x4000) overlaps previous partition u-boot (offset 0x2000, size 0x102000)
ERROR: hdimage(sdcard.img): bootloaders, etc. that overlap with the partition table must declare the overlapping area as a hole.

To fix the second genimage error report, update the size of bootloader
file. Do not reserve additional space for GPT partition table since
new genimage is able to keep track of it.

Fixes https://gitlab.com/buildroot.org/buildroot/-/jobs/1915006300

Signed-off-by: Sergey Matyukevich <[email protected]>
Signed-off-by: Thomas Petazzoni <[email protected]>