configs/nitrogen6sx: Linux needs host-openssl

The kernel configuration used for the nitrogen6x defconfig needs
host-openssl.

Fixes:

  https://gitlab.com/buildroot.org/buildroot/-/jobs/674934095

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

configs/nitrogen6sx_defconfig

@@ -40,3 +40,4 @@ BR2_LINUX_KERNEL_DEFCONFIG="boundary"
 BR2_LINUX_KERNEL_INSTALL_TARGET=y
 BR2_LINUX_KERNEL_DTS_SUPPORT=y
 BR2_LINUX_KERNEL_INTREE_DTS_NAME="imx6sx-nitrogen6sx imx6sx-nitrogen6sx-m4"
+BR2_LINUX_KERNEL_NEEDS_HOST_OPENSSL=y