build: avoid older gcc warning

Jim Fehlig reported a compilation error with older gcc 4.3.4:

libvirt.c: In function 'virDomainGetEmulatorPinInfo':
libvirt.c:9111: error: logical '&&' with non-zero constant will always evaluate as true [-Wlogical-op]

It looks like someone programmed via too much copy-and-paste.

* src/libvirt.c (virDomainGetEmulatorPinInfo): Multiplying by 1 is
a no-op, and thus will never overflow.
(cherry picked from commit 3da355e8)

src/libvirt.c

@@ -9102,11 +9102,6 @@ virDomainGetEmulatorPinInfo(virDomainPtr domain, unsigned char *cpumap,
         virLibDomainError(VIR_ERR_INVALID_ARG, __FUNCTION__);
         goto error;
     }
-    if (INT_MULTIPLY_OVERFLOW(1, maplen)) {
-        virLibDomainError(VIR_ERR_OVERFLOW, _("input too large: 1 * %d"),
-                          maplen);
-        goto error;
-    }
 
     /* At most one of these two flags should be set.  */
     if ((flags & VIR_DOMAIN_AFFECT_LIVE) &&