KVM: Make KVM_HPAGES_PER_HPAGE unsigned long to avoid build error on powerpc

Eliminates this compiler warning:

arch/powerpc/kvm/../../../virt/kvm/kvm_main.c:1178: error: integer overflow in expression
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NAvi Kivity <avi@redhat.com>

arch/powerpc/include/asm/kvm_host.h

@@ -34,7 +34,7 @@
 #define KVM_COALESCED_MMIO_PAGE_OFFSET 1
 
 /* We don't currently support large pages. */
-#define KVM_PAGES_PER_HPAGE (1<<31)
+#define KVM_PAGES_PER_HPAGE (1UL << 31)
 
 struct kvm;
 struct kvm_run;