KVM: no space before tabs in kvm_main.c

WARNING: please, no space before tabs
+ * ^I^Ikvm->lock --> kvm->slots_lock --> kvm->irq_lock$

WARNING: please, no space before tabs
+^I^I * ^I- gfn_to_hva (kvm_read_guest, gfn_to_pfn)$

WARNING: please, no space before tabs
+^I^I * ^I- kvm_is_visible_gfn (mmu_check_roots)$

This patch fixes these warnings to reduce noise when checking new
patches in kvm_main.c.
Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>