KVM: x86: Rename gb_page_enable() to get_lpage_level() in kvm_x86_ops

Then the callback can provide the maximum supported large page level, which
is more flexible.

Also move the gb page support into x86_64 specific.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index b373ae6..cf64fc0 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2911,9 +2911,9 @@
 	{ -1, NULL }
 };
 
-static bool svm_gb_page_enable(void)
+static int svm_get_lpage_level(void)
 {
-	return true;
+	return PT_PDPE_LEVEL;
 }
 
 static bool svm_rdtscp_supported(void)
@@ -2986,7 +2986,7 @@
 	.get_mt_mask = svm_get_mt_mask,
 
 	.exit_reasons_str = svm_exit_reasons_str,
-	.gb_page_enable = svm_gb_page_enable,
+	.get_lpage_level = svm_get_lpage_level,
 
 	.cpuid_update = svm_cpuid_update,