KVM: function declaration parameter name cleanup

The kvm_host.h file for x86 declares the functions kvm_set_cr[0348]. In the
header file their second parameter is named cr0 in all cases. This patch
renames the parameters so that they match the function name.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>