xen/Arm: vGICv3: Sysreg emulation is applicable for AArch64 only

Sysreg emulation is 64-bit specific, so guard the calls to
vgic_v3_emulate_sysreg() as well as the function itself with
"#ifdef CONFIG_ARM_64".

Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@amd.com>
Reviewed-by: Michal Orzel <michal.orzel@amd.com>
Acked-by: Julien Grall <julien@xen.org>

xen/arch/arm/vgic-v3.c

@@ -1510,6 +1510,7 @@ static bool vgic_v3_emulate_sgi1r(struct cpu_user_regs *regs, uint64_t *r,
     }
 }
 
+#ifdef CONFIG_ARM_64
 static bool vgic_v3_emulate_sysreg(struct cpu_user_regs *regs, union hsr hsr)
 {
     struct hsr_sysreg sysreg = hsr.sysreg;
@@ -1530,6 +1531,7 @@ static bool vgic_v3_emulate_sysreg(struct cpu_user_regs *regs, union hsr hsr)
         return false;
     }
 }
+#endif
 
 static bool vgic_v3_emulate_cp64(struct cpu_user_regs *regs, union hsr hsr)
 {
@@ -1553,8 +1555,10 @@ static bool vgic_v3_emulate_reg(struct cpu_user_regs *regs, union hsr hsr)
 {
     switch (hsr.ec)
     {
+#ifdef CONFIG_ARM_64
     case HSR_EC_SYSREG:
         return vgic_v3_emulate_sysreg(regs, hsr);
+#endif
     case HSR_EC_CP15_64:
         return vgic_v3_emulate_cp64(regs, hsr);
     default: