MIPS: idle: add case for CPU_5KE

While the 5KE processors have never been taped out, they exists though
a CP0.PRId and experimental RTLs or QEMU implementations. Add a case
entry in the idle code, as they can use the standard idle loop like the
5K processors.
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11099/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/kernel/idle.c

@@ -165,6 +165,7 @@ void __init check_wait(void)
 	case CPU_4KEC:
 	case CPU_4KSC:
 	case CPU_5KC:
+	case CPU_5KE:
 	case CPU_25KF:
 	case CPU_PR4450:
 	case CPU_BMIPS3300: