Revert "jbd2: optimize jbd2_journal_force_commit"

This reverts commit 7d96eeae128520ae7bc408941512417c49422252.
Revert "ARM: Use -mcpu=cortex-a15 when targeting MSM Krait CPUs"

This reverts commit 34091d2643667ba1af3ecdb4d0026de63bd751e8.
restored old optimizations (new ones caused reboots)