opal-api: Drop diagnostics data type symbol for PHB5
opal-api: Drop diagnostics data type symbol for PHB5

All PHB5 error registers read when getting the PHB diagnostics data
have the exact same definitions as on PHB4, so we don't need any new
type. OPAL_PHB_ERROR_DATA_TYPE_PHB5 is not used in skiboot. It's
never been imported on linux, so it is safe to remove the symbol.

Signed-off-by: Frederic Barrat <c90240987c583ac0802fbeb88cb1684edc683e18@linux.ibm.com>
Signed-off-by: Vasant Hegde <a6d753843573f7bfed5075c1e875b0be8007a0ab@linux.vnet.ibm.com>

shenki/skiboot,qemu/skiboot,shenki/skiboot,open-power/skiboot,open-power/skiboot,qemu/skiboot,legoater/skiboot,open-power/skiboot,legoater/skiboot,open-power/skiboot,shenki/skiboot,shenki/skiboot,legoater/skiboot,legoater/skiboot,qemu/skiboot,shenki/skiboot,qemu/skiboot,legoater/skiboot,open-power/skiboot,qemu/skiboot