Revert 15770 develop a6910f900 gelu mkl opt

[tensor-tang]

@yihuaxu since the problem below, we should revert firstly.

CE job failed. http://ce.paddlepaddle.org:8080/viewLog.html?buildId=27374&buildTypeId=PaddleModesl_BuildModels

[tensor-tang]

revert 的code中有改动cmake， 需要 @panyx0718 approve

Step 1/1] + echo 'checking cmake/external change, PR: 15872, changes: cmake/external/mklml.cmake'
[06:28:48][Step 1/1] + '[' cmake/external/mklml.cmake ']'
[06:28:48][Step 1/1] + '[' 15872 '!=' '' ']'
[06:28:48][Step 1/1] checking cmake/external change, PR: 15872, changes: cmake/external/mklml.cmake
[06:28:48][Step 1/1] ++ curl -H 'Authorization: token 95a329e820eeae12c4c5c8a0b6e3e39654dc01a4' 'https://api.github.com/repos/PaddlePaddle/Paddle/pulls/15872/reviews?per_page=10000'
[06:28:48][Step 1/1] ++ python /paddle/tools/check_pr_approval.py 1 2887803
[06:28:48][Step 1/1]   % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
[06:28:48][Step 1/1]                                  Dload  Upload   Total   Spent    Left  Speed
[06:28:49][Step 1/1] 
[06:28:49][Step 1/1]   0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
[06:28:50][Step 1/1]   0     0    0     0    0     0      0      0 --:--:--  0:00:01 --:--:--     0
[06:28:50][Step 1/1] 100  1770  100  1770    0     0   1151      0  0:00:01  0:00:01 --:--:--  1151
[06:28:50][Step 1/1] current pr 15872 got approvals: FALSE
[06:28:50][Step 1/1] You must have panyx0718 approval for the api change! cmake/external
[06:28:50][Step 1/1] + APPROVALS=FALSE
[06:28:50][Step 1/1] + echo 'current pr 15872 got approvals: FALSE'
[06:28:50][Step 1/1] + '[' FALSE == FALSE ']'
[06:28:50][Step 1/1] + echo 'You must have panyx0718 approval for the api change! cmake/external'
[06:28:50][Step 1/1] + exit 1