package/linux-headers: drop 6.0.x option

The 6.0.x series is now EOL upstream, so drop the linux-headers option and
add legacy handling for it.

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

Config.in.legacy

@@ -146,6 +146,13 @@ endif
 
 comment "Legacy options removed in 2023.02"
 
+config BR2_KERNEL_HEADERS_6_0
+	bool "kernel headers version 6.0.x are no longer supported"
+	select BR2_LEGACY
+	help
+	  Version 6.0.x of the Linux kernel headers are no longer
+	  maintained upstream and are now removed.
+
 config BR2_KERNEL_HEADERS_4_9
 	bool "kernel headers version 4.9.x are no longer supported"
 	select BR2_LEGACY

linux/linux.hash

@@ -1,6 +1,5 @@
 # From https://www.kernel.org/pub/linux/kernel/v6.x/sha256sums.asc
 sha256  581b0560077863c5116512c0b5fd93b97814092c80e6ebebabe88101949af7a1  linux-6.1.11.tar.xz
-sha256  abe37eb0e2e331bdc7c4110115664e180e7d43b7336de6b4cd2bd1b123d30207  linux-6.0.19.tar.xz
 # From https://www.kernel.org/pub/linux/kernel/v5.x/sha256sums.asc
 sha256  e7ed24f2690bf0e11158ccfa8ddc5c0e8a4816d83c4055d205218853da9c5dad  linux-5.15.93.tar.xz
 sha256  d807f97812e566410cd13b3170009e0d7552748d4f22d608ffd4dbd7f85bf9c6  linux-5.10.167.tar.xz

package/linux-headers/Config.in.host

@@ -45,10 +45,6 @@ config BR2_KERNEL_HEADERS_5_15
 	bool "Linux 5.15.x kernel headers"
 	select BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_15
 
-config BR2_KERNEL_HEADERS_6_0
-	bool "Linux 6.0.x kernel headers"
-	select BR2_TOOLCHAIN_HEADERS_AT_LEAST_6_0
-
 config BR2_KERNEL_HEADERS_6_1
 	bool "Linux 6.1.x kernel headers"
 	select BR2_TOOLCHAIN_HEADERS_AT_LEAST_6_1
@@ -393,7 +389,6 @@ config BR2_DEFAULT_KERNEL_HEADERS
 	default "5.4.231"	if BR2_KERNEL_HEADERS_5_4
 	default "5.10.167"	if BR2_KERNEL_HEADERS_5_10
 	default "5.15.93"	if BR2_KERNEL_HEADERS_5_15
-	default "6.0.19"	if BR2_KERNEL_HEADERS_6_0
 	default "6.1.11"	if BR2_KERNEL_HEADERS_6_1
 	default BR2_DEFAULT_KERNEL_VERSION if BR2_KERNEL_HEADERS_VERSION
 	default "custom"	if BR2_KERNEL_HEADERS_CUSTOM_TARBALL