[source] ramips: Fix sdhci kernel panics on MT7621

[LEDE Commits]

blogic pushed a commit to source.git, branch master:
https://git.lede-project.org/605cab749e04d836bc6756c1e11e895406a3eef3

commit 605cab749e04d836bc6756c1e11e895406a3eef3
Author: Andrew Yong <me at ndoo.sg>
AuthorDate: Mon Nov 21 15:14:16 2016 +0800

    ramips: Fix sdhci kernel panics on MT7621
    
    Enable work-arounds present in the code commented-out but needed to write to
    sdcard on mt7621 which currently causes kernel to oops when engaging in
    serious writing to sdcard. With this change applied, there are still
    occasional warnings thrown by the mmc driver, however, at least it no longer
    crashes the system and even large writes (full-card dump/erase/write/compare)
    don't show any corruption.
    
    Signed-off-by: Daniel Golle <daniel at makrotopia.org>
    
    Rebase to LEDE and added "CONFIG_SOC_MT7621" check to ensure non-MT7621 devices do not face performance regressions.
    Signed-off-by: Andrew Yong <me at ndoo.sg>
---
 .../patches-4.4/0046-mmc-MIPS-ralink-add-sdhci-for-mt7620a-SoC.patch  | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/target/linux/ramips/patches-4.4/0046-mmc-MIPS-ralink-add-sdhci-for-mt7620a-SoC.patch b/target/linux/ramips/patches-4.4/0046-mmc-MIPS-ralink-add-sdhci-for-mt7620a-SoC.patch
index b36c77c..348b563 100644
--- a/target/linux/ramips/patches-4.4/0046-mmc-MIPS-ralink-add-sdhci-for-mt7620a-SoC.patch
+++ b/target/linux/ramips/patches-4.4/0046-mmc-MIPS-ralink-add-sdhci-for-mt7620a-SoC.patch
@@ -3906,8 +3906,8 @@ Signed-off-by: John Crispin <blogic at openwrt.org>
 +    host->mrq = mrq;    
 +
 +    if (msdc_do_request(mmc,mrq)) {  	
-+        if(host->hw->flags & MSDC_REMOVABLE && mrq->data && mrq->data->error) {
-+            //msdc_tune_request(mmc,mrq);                                    	
++        if(host->hw->flags & MSDC_REMOVABLE && CONFIG_SOC_MT7621 && mrq->data && mrq->data->error) {
++            msdc_tune_request(mmc,mrq);                                    	
 +        }        	
 +    }
 +