configs/cubieboard{1, 2}: bump Linux to 6.19.6 and U-Boot to 2026.01

This commit will also switch to the Bootlin glibc stable toolchain.

Switch to Bootlin glibc stable toolchain as requested by the 2024
Buildroot meeting report:
https://elinux.org/Buildroot:DeveloperDaysELCE2024#Rules_for_defconfigs

Signed-off-by: Scott Fan <fancp2007@gmail.com>
[Julien:
 - remove no longer needed linux-headers.hash
 - change comment in linux.hash to take hash from upstream
]
Signed-off-by: Julien Olivain <ju.o@free.fr>

board/cubietech/cubieboard1/patches/linux-headers/linux-headers.hash

@@ -1 +0,0 @@
-../linux/linux.hash

board/cubietech/cubieboard1/patches/linux/linux.hash

@@ -1,2 +1,2 @@
-# Locally calculated
-sha256  b4850cf670a032c70f38b713a27d62046c5f747caf028c5f50b18f98606a9eb1  linux-6.12.52.tar.xz
+# From https://www.kernel.org/pub/linux/kernel/v6.x/sha256sums.asc
+sha256  4d9f3ff73214f68c0194ef02db9ca4b7ba713253ac1045441d4e9f352bc22e14  linux-6.19.6.tar.xz

board/cubietech/cubieboard1/patches/uboot/uboot.hash

@@ -1,2 +1,2 @@
 # Locally calculated
-sha256  b4f032848e56cc8f213ad59f9132c084dbbb632bc29176d024e58220e0efdf4a  u-boot-2025.10.tar.bz2
+sha256  b60d5865cefdbc75da8da4156c56c458e00de75a49b80c1a2e58a96e30ad0d54  u-boot-2026.01.tar.bz2

board/cubietech/cubieboard2/patches/linux-headers/linux-headers.hash

@@ -1 +0,0 @@
-../linux/linux.hash

board/cubietech/cubieboard2/patches/linux/linux.hash

@@ -1,2 +1,2 @@
-# Locally calculated
-sha256  b4850cf670a032c70f38b713a27d62046c5f747caf028c5f50b18f98606a9eb1  linux-6.12.52.tar.xz
+# From https://www.kernel.org/pub/linux/kernel/v6.x/sha256sums.asc
+sha256  4d9f3ff73214f68c0194ef02db9ca4b7ba713253ac1045441d4e9f352bc22e14  linux-6.19.6.tar.xz

board/cubietech/cubieboard2/patches/uboot/uboot.hash

@@ -1,2 +1,2 @@
 # Locally calculated
-sha256  b4f032848e56cc8f213ad59f9132c084dbbb632bc29176d024e58220e0efdf4a  u-boot-2025.10.tar.bz2
+sha256  b60d5865cefdbc75da8da4156c56c458e00de75a49b80c1a2e58a96e30ad0d54  u-boot-2026.01.tar.bz2