msm8974: Reserve memory for ramconsole

 * Samsung's implementation of ramconsole depends on the device
   being at DEBUG_LEVEL_HIGH, which makes collecting crash logs
   from devices in the wild impossible.
 * Enable the standard ramconsole by reserving persistent ram.

Change-Id: If59e08be09db7ebba97e4dc66f2167395032d807

Conflicts:
	arch/arm/configs/msm8974_sec_defconfig
	arch/arm/mach-msm/board-8974.c