sparc64: create/destroy cpu sysfs dynamically

sparc64: create/destroy cpu sysfs dynamically

Currently, cpu/cpuX represents maximum number of possible
cpus in a domain. Those cpu sysfs directories also does
not change as we add/remove cpus via ldom manager.

Update sysfs so that it represents number of present cpus
in the domain. As a result, cpu sysfs is also updated
dynamically upon cpu add/removal.

Orabug: 21775890
Orabug: 25216469

Before the fix:
[root@ca-sparc76 ~]# ldm list
NAME             STATE      FLAGS   CONS VCPU  MEMORY UTIL  NORM  UPTIME
primary          active     -n-cv-  UART 32    32G    0.2%  0.2%  11m

[root@ca-sparc76 ~]# getconf _NPROCESSORS_CONF
512
[root@ca-sparc76 ~]# ldm set-vcpu 64 primary
[root@ca-sparc76 ~]# ldm list
NAME             STATE      FLAGS   CONS VCPU  MEMORY UTIL  NORM  UPTIME
primary          active     -n-cv-  UART 64    32G    0.0%  0.0%  12m
[root@ca-sparc76 ~]# getconf _NPROCESSORS_CONF
512
-------------------------------------------------------------------------
After the fix:
[root@ca-sparc76 ~]# getconf _NPROCESSORS_CONF
32
[root@ca-sparc76 ~]# ldm set-vcpu 64 primary
[root@ca-sparc76 ~]# ldm list
NAME             STATE      FLAGS   CONS  VCPU  MEMORY UTIL  NORM  UPTIME
primary          active     -n-cv-  UART  64    32G    0.0%  0.0%  12m
[root@ca-sparc76 ~]# getconf _NPROCESSORS_CONF
64

Signed-off-by: Atish Patra <atish.patra@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Thomas Tai <thomas.tai@oracle.com>
Signed-off-by: Allen Pais <allen.pais@oracle.com>