x86, kvm: Fix intialization warnings in kvm.c

With commit:

  4cca6ea0 ("x86/apic: Allow x2apic without IR on VMware platform")

we started seeing "incompatible initialization" warning messages,
since x2apic_available() expects a bool return type while
kvm_para_available() returns an int.

Reported by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NAlok N Kataria <akataria@vmware.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

arch/x86/include/asm/kvm_para.h

@@ -85,13 +85,13 @@ static inline long kvm_hypercall4(unsigned int nr, unsigned long p1,
 	return ret;
 }
 
-static inline int kvm_para_available(void)
+static inline bool kvm_para_available(void)
 {
 	unsigned int eax, ebx, ecx, edx;
 	char signature[13];
 
 	if (boot_cpu_data.cpuid_level < 0)
-		return 0;	/* So we don't blow up on old processors */
+		return false;	/* So we don't blow up on old processors */
 
 	if (cpu_has_hypervisor) {
 		cpuid(KVM_CPUID_SIGNATURE, &eax, &ebx, &ecx, &edx);
@@ -101,10 +101,10 @@ static inline int kvm_para_available(void)
 		signature[12] = 0;
 
 		if (strcmp(signature, "KVMKVMKVM") == 0)
-			return 1;
+			return true;
 	}
 
-	return 0;
+	return false;
 }
 
 static inline unsigned int kvm_arch_para_features(void)