target/hppa: Add missing PL1 and PL2 privilege levels

The hppa CPU has 4 privilege levels (0-3).
Mention the missing PL1 and PL2 levels, although the Linux kernel
uses only 0 (KERNEL) and 3 (USER). Not sure about HP-UX.

Signed-off-by: Helge Deller <deller@gmx.de>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

target/hppa/cpu.h

@@ -31,8 +31,11 @@
 #define TCG_GUEST_DEFAULT_MO        TCG_MO_ALL
 
 #define MMU_KERNEL_IDX   0
+#define MMU_PL1_IDX      1
+#define MMU_PL2_IDX      2
 #define MMU_USER_IDX     3
 #define MMU_PHYS_IDX     4
+
 #define TARGET_INSN_START_EXTRA_WORDS 1
 
 /* Hardware exceptions, interrupts, faults, and traps.  */