x86: Fix AMD_SVM and INTEL_VMX dependency

Commit e3ed540f2e was meant to make AMD_SVM dependent on AMD and
INTEL_VMX on INTEL. This dependency was reflected using 'if' next to a
prompt which is incorrect as it that deals only with the visibility of the
given Kconfig option. This makes it impossible to e.g. disable INTEL_VMX
when INTEL is disabled (option is hidden). Fix it while keeping the
possibility of e.g. enabling INTEL_VMX when INTEL is disabled.

Fixes: e3ed540f2e ("x86/hvm: add HVM-specific Kconfig")
Signed-off-by: Michal Orzel <michal.orzel@amd.com>
Acked-by: Jan Beulich <jbeulich@suse.com>

xen/arch/x86/hvm/Kconfig

@@ -16,8 +16,8 @@ menuconfig HVM
 if HVM
 
 config AMD_SVM
-	bool "AMD-V" if AMD && EXPERT
-	default y
+	bool "AMD-V" if EXPERT
+	default AMD
 	help
 	  Enables virtual machine extensions on platforms that implement the
 	  AMD Virtualization Technology (AMD-V).
@@ -25,8 +25,8 @@ config AMD_SVM
 	  If in doubt, say Y.
 
 config INTEL_VMX
-	bool "Intel VT-x" if INTEL && EXPERT
-	default y
+	bool "Intel VT-x" if EXPERT
+	default INTEL
 	select ARCH_VCPU_IOREQ_COMPLETION
 	help
 	  Enables virtual machine extensions on platforms that implement the