kernel-rt from Kernel:SLE15-SP4-RT-LTSS project

需要 pool ，用 root 執行：

zypper addrepo https://download.opensuse.org/repositories/Kernel:SLE15-SP4-RT-LTSS/pool/Kernel:SLE15-SP4-RT-LTSS.repo
zypper refresh
zypper install kernel-rt