bhyve: fix ATTRIBUTE_NONNULL usage

Fix incorrect ATTRIBUTE_NONNULL usage introduced in 17b17565
which caused build failure:

bhyve/bhyve_driver.c:127:48: error: expected ')'
bhyveDriverGetCapabilities(bhyveConnPtr driver ATTRIBUTE_NONNULL)
                                               ^
bhyve/bhyve_driver.c:127:27: note: to match this '('
bhyveDriverGetCapabilities(bhyveConnPtr driver ATTRIBUTE_NONNULL)

Pushed under the build breaker rule.

src/bhyve/bhyve_driver.c

@@ -123,8 +123,8 @@ bhyveAutostartDomains(bhyveConnPtr driver)
  *
  * Returns: a reference to a virCapsPtr instance or NULL
  */
-static virCapsPtr
-bhyveDriverGetCapabilities(bhyveConnPtr driver ATTRIBUTE_NONNULL)
+static virCapsPtr ATTRIBUTE_NONNULL(1)
+bhyveDriverGetCapabilities(bhyveConnPtr driver)
 {
 
     return virObjectRef(driver->caps);