target-arm: Implement AArch64 OSLAR_EL1 sysreg as WI

Define a dummy version of the AArch64 OSLAR_EL1 system register
which just ignores writes. Linux will always write to this (it
is the OS lock used for debugging), but we don't support debug.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NPeter Crosthwaite <peter.crosthwaite@xilinx.com>

target-arm/helper.c

@@ -1738,6 +1738,10 @@ static const ARMCPRegInfo v8_cp_reginfo[] = {
     { .name = "MDSCR_EL1", .state = ARM_CP_STATE_AA64,
       .opc0 = 2, .opc1 = 0, .crn = 0, .crm = 2, .opc2 = 2,
       .access = PL1_RW, .type = ARM_CP_CONST, .resetvalue = 0 },
+    /* We define a dummy WI OSLAR_EL1, because Linux writes to it. */
+    { .name = "OSLAR_EL1", .state = ARM_CP_STATE_AA64,
+      .opc0 = 2, .opc1 = 0, .crn = 1, .crm = 0, .opc2 = 4,
+      .access = PL1_W, .type = ARM_CP_NOP },
     REGINFO_SENTINEL
 };