build: use tar-ustar to allow paths longer than 99

Needed to fix these errors:

  tar: osmo-iuh-UNKNOWN-dirty/include/osmocom/ranap/RANAP_SourceeNodeB-ToTargeteNodeB-TransparentContainer.h: file name is too long (max 99); not dumped
  tar: osmo-iuh-UNKNOWN-dirty/include/osmocom/ranap/RANAP_LocationRelatedDataRequestTypeSpecificToGERANIuMode.h: file name is too long (max 99); not dumped
  tar: osmo-iuh-UNKNOWN-dirty/include/osmocom/ranap/RANAP_TargeteNodeB-ToSourceeNodeB-TransparentContainer.h: file name is too long (max 99); not dumped
  tar: osmo-iuh-UNKNOWN-dirty/include/osmocom/ranap/RANAP_Requested-RAB-Parameter-ExtendedGuaranteedBitrateList.h: file name is too long (max 99); not dumped

Change-Id: Id41bca92810a81ac50697c0230a6caef490b0ffd
1 file changed