configs/imx6slevk: bump the kernel version

Bump the kernel version to 5.15.11.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

configs/imx6slevk_defconfig

@@ -3,8 +3,8 @@ BR2_cortex_a9=y
 BR2_ARM_ENABLE_NEON=y
 BR2_ARM_ENABLE_VFP=y
 BR2_ARM_FPU_VFPV3=y
-# Linux headers same as kernel, a 4.14 series
-BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_14=y
+# Linux headers same as kernel, a 5.15 series
+BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_5_15=y
 BR2_TARGET_GENERIC_GETTY_PORT="ttymxc0"
 BR2_TARGET_ROOTFS_EXT2=y
 BR2_TARGET_ROOTFS_EXT2_4=y
@@ -15,7 +15,7 @@ BR2_TARGET_UBOOT_CUSTOM_VERSION_VALUE="2021.10"
 BR2_TARGET_UBOOT_FORMAT_IMX=y
 BR2_LINUX_KERNEL=y
 BR2_LINUX_KERNEL_CUSTOM_VERSION=y
-BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.14"
+BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="5.15.11"
 BR2_LINUX_KERNEL_DEFCONFIG="imx_v6_v7"
 BR2_LINUX_KERNEL_DTS_SUPPORT=y
 BR2_LINUX_KERNEL_INTREE_DTS_NAME="imx6sl-evk"