ARM: dts: msm8974: Allow power collapse as minimum l2 gdhs mode

This fixes warnings "IRQ40 no longer affine to CPUn". The switch
to C2 is also hardly understandable.
Revert "cpufreq_ondemand: Remove notifiers"

This reverts commit 373cafa0d8a3043ce37fd48df8cf9cbfb9276990.
Re-enable all of the debugging
Makefile: Subarch is not 'arm'

Derp.
cpufreq_interactive: Import from CAF kk_3.5

Not using this governor anymore so may as well sync it with CAF for consistency.
Sultan_defconfig: Re-enable all of the debugging
Sultan_defconfig: Disable excessive cache debugging

Qualcomm recommends disabling these options for production builds. Specifically, CONFIG_MSM_L1_RECOV_ERR_PANIC is causing the kernel to panic when a recoverable cache error occurs, which is unnecessary.