main/linux-lts: enable CIFS_UPCALL on all arches

This sets CONFIG_CIFS_UPCALL=y on all platform.

This item allows the kernel to call a userspace process during a mount -t cifs, depending on options provided in -o (here -o sec=krb5 or sec=krb5i). This mechanism is required to use Kerberos authentication, combined with keyutils and cifs-utils. keyutils contains /sbin/request-key, the userspace process called by the kernel.

Tested successfully on virt-amd64