efi: Adjust copyright and mention constant source

While the file where the basename.c code came from is marked as Linaro
from 2020, commit [1] was based on Heinrich's email. Also, [2] and [3]
were my patches. Linaro is not the copyright holder and none of the code
is from 2020.

Update the file accordingly.

Link: https://lore.kernel.org/u-boot/2175cecb-a392-5107-b932-b099ec21d62c@gmx.de
[1] 4e65ca00f3 ("efi_loader: bootmgr: add booting from removable media")
[2] 3e18860e3f ("bootstd: Allow reading an EFI file from the network")
[3] 7506c15669 ("sandbox: Report host default-filename in native mode")

Signed-off-by: Simon Glass <sjg@chromium.org>
Suggested-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

lib/efi/basename.c

@@ -1,6 +1,6 @@
-// SPDX-License-Identifier: GPL-2.0+
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
- * Copyright (c) 2020, Linaro Limited
+ * Copyright (c) 2022, Heinrich Schuchardt <xypron.glpk@gmx.de>
  */
 
 #define LOG_CATEGORY LOGC_EFI
@@ -12,6 +12,12 @@
 
 #undef BOOTEFI_NAME
 
+/*
+ * The constants below come from:
+ *
+ * https://www.iana.org/assignments/dhcpv6-parameters/dhcpv6-parameters.xhtml#processor-architecture
+ */
+
 #if HOST_ARCH == HOST_ARCH_X86_64
 #define HOST_BOOTEFI_NAME "BOOTX64.EFI"
 #define HOST_PXE_ARCH 0x6