[source] ar71xx: enable serial console on mikrotik devices

[LEDE Commits]

mkresin pushed a commit to source.git, branch master:
https://git.lede-project.org/5dd13c071b4c5a5d45abb1dea2a0978c3f11890e

commit 5dd13c071b4c5a5d45abb1dea2a0978c3f11890e
Author: João Chaínho <joaochainho at gmail.com>
AuthorDate: Thu Nov 17 22:15:42 2016 +0000

    ar71xx: enable serial console on mikrotik devices
    
    This patch enables the serial console on some Mikrotik devices (RB450,
    RB450G, RB493G, RB750UP).
    
    Signed-off-by: João Chaínho <joaochainho at gmail.com>
---
 .../patches-4.4/701-MIPS-ath79-add-routerboard-detection.patch       | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/target/linux/ar71xx/patches-4.4/701-MIPS-ath79-add-routerboard-detection.patch b/target/linux/ar71xx/patches-4.4/701-MIPS-ath79-add-routerboard-detection.patch
index 8dee006..77bf38c 100644
--- a/target/linux/ar71xx/patches-4.4/701-MIPS-ath79-add-routerboard-detection.patch
+++ b/target/linux/ar71xx/patches-4.4/701-MIPS-ath79-add-routerboard-detection.patch
@@ -1,11 +1,14 @@
 --- a/arch/mips/ath79/prom.c
 +++ b/arch/mips/ath79/prom.c
-@@ -136,6 +136,13 @@ void __init prom_init(void)
+@@ -136,6 +136,16 @@ void __init prom_init(void)
  		initrd_end = initrd_start + fw_getenvl("initrd_size");
  	}
  #endif
 +
 +	if (strstr(arcs_cmdline, "board=750Gr3") ||
++	    strstr(arcs_cmdline, "board=750i") ||
++	    strstr(arcs_cmdline, "board=450") ||
++	    strstr(arcs_cmdline, "board=493") ||
 +	    strstr(arcs_cmdline, "board=951G") ||
 +	    strstr(arcs_cmdline, "board=2011L") ||
 +	    strstr(arcs_cmdline, "board=711Gr100") ||