qemu_riscv64_nommu_virt_defconfig: specify kernel headers version

The defconfigs uses a 5.19 kernel, so specify 5.19 kernel headers now that
is available.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

configs/qemu_riscv64_nommu_virt_defconfig

@@ -3,6 +3,9 @@ BR2_riscv=y
 BR2_RISCV_64=y
 # BR2_RISCV_USE_MMU is not set
 
+# Linux headers same as kernel, a 5.19 series
+BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_5_19=y
+
 # Busybox with hush
 BR2_PACKAGE_BUSYBOX_CONFIG="package/busybox/busybox-minimal.config"