x86/mce: remove ASSERT's about mce_[u|d]handler_num in mce_action()

Those assertions as well as mce_[u|d]handlers[], mce_[u|d]handler_num
and mce_action() were intel only and lifted to the common code by c/s
3a91769d6e. However, MCE handling on AMD does not use mce_[u|d]handlers[]
before and after that commit, so assertions in mce_action() about their
size do not make sense for AMD. To be worse, they can crash the debug
build on AMD. Remove them to make the debug build work on AMD.

Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

xen/arch/x86/cpu/mcheck/mce.c

@@ -1616,9 +1616,6 @@ static enum mce_result mce_action(const struct cpu_user_regs *regs,
         handlers = mce_uhandlers;
     }
 
-    /* At least a default handler should be registerd */
-    ASSERT(handler_num);
-
     local_mi = (struct mc_info*)mctelem_dataptr(mctc);
     x86_mcinfo_lookup(mic, local_mi, MC_TYPE_GLOBAL);
     if (mic == NULL) {
@@ -1651,7 +1648,6 @@ static enum mce_result mce_action(const struct cpu_user_regs *regs,
                 break;
             }
         }
-        ASSERT(i != handler_num);
     }
 
     return worst_result;