[source] arm64: fix build for linux 4.4.21

[LEDE Commits]

noltari pushed a commit to source.git, branch master:
https://git.lede-project.org/8c52fbbe3ab0abd01fd8710dd0a5311d15d2b169

commit 8c52fbbe3ab0abd01fd8710dd0a5311d15d2b169
Author: Álvaro Fernández Rojas <noltari at gmail.com>
AuthorDate: Fri Sep 16 12:11:10 2016 +0200

    arm64: fix build for linux 4.4.21
    
    linux 4.4.21 adds 2 new symbols for arm64.
    
    Signed-off-by: Álvaro Fernández Rojas <noltari at gmail.com>
---
 target/linux/arm64/config-4.4 | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/target/linux/arm64/config-4.4 b/target/linux/arm64/config-4.4
index d6f5ae6..d3f7f75 100644
--- a/target/linux/arm64/config-4.4
+++ b/target/linux/arm64/config-4.4
@@ -81,7 +81,9 @@ CONFIG_BSD_PROCESS_ACCT=y
 CONFIG_BSD_PROCESS_ACCT_V3=y
 CONFIG_BUILD_BIN2C=y
 # CONFIG_CAVIUM_ERRATUM_22375 is not set
+# CONFIG_CAVIUM_ERRATUM_23144 is not set
 # CONFIG_CAVIUM_ERRATUM_23154 is not set
+# CONFIG_CAVIUM_ERRATUM_27456 is not set
 CONFIG_CC_OPTIMIZE_FOR_SIZE=y
 CONFIG_CLKDEV_LOOKUP=y
 CONFIG_CLKSRC_ACPI=y