KVM: x86: Use octal for file permission

Convert all module params to octal permissions to improve code readability
and to make checkpatch happy:

  WARNING: Symbolic permissions 'S_IRUGO' are not preferred. Consider using
           octal permissions '0444'.

Signed-off-by: Peng Hao <flyingpeng@tencent.com>
Link: https://lore.kernel.org/r/20231013113020.77523-1-flyingpeng@tencent.com


Signed-off-by: Sean Christopherson <seanjc@google.com>