i386/monitor: Support EGPRs in hmp_print

Add EGPRs in monitor_defs[] to allow HMP to access EGPRs.

For example,

(qemu) print $r16

Since monitor_defs[] is used for read-only case, no need to consider
xstate synchronization issues that might be caused by modifying EGPRs
(like what gdbstub did).

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Tested-by: Xudong Hao <xudong.hao@intel.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20251211070942.3612547-7-zhao1.liu@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

target/i386/monitor.c

@@ -623,6 +623,22 @@ const MonitorDef monitor_defs[] = {
     { "r13", offsetof(CPUX86State, regs[13]) },
     { "r14", offsetof(CPUX86State, regs[14]) },
     { "r15", offsetof(CPUX86State, regs[15]) },
+    { "r16", offsetof(CPUX86State, regs[16]) },
+    { "r17", offsetof(CPUX86State, regs[17]) },
+    { "r18", offsetof(CPUX86State, regs[18]) },
+    { "r19", offsetof(CPUX86State, regs[19]) },
+    { "r20", offsetof(CPUX86State, regs[20]) },
+    { "r21", offsetof(CPUX86State, regs[21]) },
+    { "r22", offsetof(CPUX86State, regs[22]) },
+    { "r23", offsetof(CPUX86State, regs[23]) },
+    { "r24", offsetof(CPUX86State, regs[24]) },
+    { "r25", offsetof(CPUX86State, regs[25]) },
+    { "r26", offsetof(CPUX86State, regs[26]) },
+    { "r27", offsetof(CPUX86State, regs[27]) },
+    { "r28", offsetof(CPUX86State, regs[28]) },
+    { "r29", offsetof(CPUX86State, regs[29]) },
+    { "r30", offsetof(CPUX86State, regs[30]) },
+    { "r31", offsetof(CPUX86State, regs[31]) },
 #endif
     { "eflags", offsetof(CPUX86State, eflags) },
     { "eip", offsetof(CPUX86State, eip) },