qemu-options: cleanup duplicated help message for kernel_irqchip

Remove the duplicated help message for 'kernel_irqchip'.

Signed-off-by: Po-Hsu Lin <po-hsu.lin@canonical.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

qemu-options.hx

@@ -32,7 +32,6 @@ DEF("machine", HAS_ARG, QEMU_OPTION_machine, \
     "                selects emulated machine ('-machine help' for list)\n"
     "                property accel=accel1[:accel2[:...]] selects accelerator\n"
     "                supported accelerators are kvm, xen, tcg (default: tcg)\n"
-    "                kernel_irqchip=on|off controls accelerated irqchip support\n"
     "                kernel_irqchip=on|off|split controls accelerated irqchip support (default=off)\n"
     "                vmport=on|off|auto controls emulation of vmport (default: auto)\n"
     "                kvm_shadow_mem=size of KVM shadow MMU in bytes\n"