configs/imx6-sabresd: needs host-openssl for the Linux kernel build

Fixes:

  https://gitlab.com/buildroot.org/buildroot/-/jobs/55306836

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

configs/imx6-sabresd_defconfig

@@ -36,3 +36,4 @@ BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.15"
 BR2_LINUX_KERNEL_DEFCONFIG="imx_v6_v7"
 BR2_LINUX_KERNEL_DTS_SUPPORT=y
 BR2_LINUX_KERNEL_INTREE_DTS_NAME="imx6q-sabresd imx6dl-sabresd imx6qp-sabresd"
+BR2_LINUX_KERNEL_NEEDS_HOST_OPENSSL=y