linux/linux.hash: fix typo in 5.1.4 entry

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

linux/linux.hash

@@ -1,5 +1,5 @@
 # From https://www.kernel.org/pub/linux/kernel/v5.x/sha256sums.asc
-sha256 5c6d65faba54652b3ab4cfcb2f3be88d53478a2cd24d0f1cdd9344c7aad1e7f9  linux-5.1.4.tar.x
+sha256 5c6d65faba54652b3ab4cfcb2f3be88d53478a2cd24d0f1cdd9344c7aad1e7f9  linux-5.1.4.tar.xz
 sha256 7fbd0b3d90a7a28a013f1e3f006c02235c12b41fd020460722a0b7c9936db0d8  linux-5.0.18.tar.xz
 # From https://www.kernel.org/pub/linux/kernel/v4.x/sha256sums.asc
 sha256 eb31e62fbb30aaeedb892cecdd8ac9746d42cbbef2ef2356f9ca8e13514b9d2b  linux-4.19.45.tar.xz