[Feature][SKL] Support disabling AVX-512

[quanxian]

Description:

On Skylake server we have some problems with AVX512/AVX2 lowering frequency and potentially lowering performance.
To do easy debug and as a potential solution it is useful to be able to disable AVX512 and AVX2
I posted patches to disable AVX512/2 at the kernel level.
Once they are merged we should back port them ASAP to server oriented distros, so that any issues on SKX deployment can be addressed.
Current patches are here
https://patchwork.kernel.org/patch/9618881/
https://patchwork.kernel.org/patch/9618883/
Note for backporting: the FPU code has been recently re-organized. So some of the patches likely need to be moved to other files and potentially other functions. But it's straight forward, so shouldn't be too difficult.

Commit Ids:

0b00de857a648dafe7020878c7a27cf776f5edf4
0c2a3913d6f50503f7c59d83a6219e39508cc898
57b8b1a1856adaa849d02d547411a553a531022b
73e3a7d2a7c3be29a5a22b85026f6cfa5664267f
cbe96375025e14fc76f9ed42ee5225120d7210f8
ccb18db2ab9d923df07e7495123fe5fb02329713

Target Kernel: 4.14

Target Release: 18.04

[Leann Ogasawara (leannogasawara)]

0b00de857a648dafe7020878c7a27cf776f5edf4 x86/cpuid: Add generic table for CPUID dependencies
v4.15-rc1~157^2~50^2~7
0c2a3913d6f50503f7c59d83a6219e39508cc898 x86/fpu: Parse clearcpuid= as early XSAVE argument
v4.15-rc1~157^2~50^2~6
57b8b1a1856adaa849d02d547411a553a531022b x86/cpuid: Prevent out of bound access in do_clear_cpu_cap()
v4.15-rc1~157^2~50^2~3
73e3a7d2a7c3be29a5a22b85026f6cfa5664267f x86/fpu: Remove the explicit clearing of XSAVE dependent features
v4.15-rc1~157^2~50^2~4
cbe96375025e14fc76f9ed42ee5225120d7210f8 bitops: Add clear/set_bit32() to linux/bitops.h
v4.15-rc1~157^2~50^2~8
ccb18db2ab9d923df07e7495123fe5fb02329713 x86/fpu: Make XSAVE check the base CPUID features before enabling
v4.15-rc1~157^2~50^2~5

[Leann Ogasawara (leannogasawara)]

4.15 is now available in Bionic. Marking this Fix Released.