[MIPS] Fix detection and handling of the 74K processor.

Nothing exciting; Linux just didn't know it yet so this is most adding
a value to a case statement.
    
Signed-off-by: Chris Dearman <chris@mips.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/mm/tlbex.c

@@ -906,6 +906,7 @@ static __init void build_tlb_write_entry(u32 **p, struct label **l,
 	case CPU_4KEC:
 	case CPU_24K:
 	case CPU_34K:
+	case CPU_74K:
 		i_ehb(p);
 		tlbw(p);
 		break;