Increase memory size from 2048 to 4096 for PowerPC
as today seems to be required to avoid createhdds to hang
on creation of disk_f25_minimal_2_ppc64le.img.tmp ...[13/22]
Trying to VNC connect, show anaconda menu stuck on
"Performing post-installation setup tasks"
Signed-off-by: Michel Normand <normand@linux.vnet.ibm.com>