staging: ram_console: Fix section mismatches

WARNING: vmlinux.o(.text+0x25d5fc): Section mismatch in reference
from the function ram_console_driver_probe() to the function
.init.text:ram_console_init()
The function ram_console_driver_probe() references
the function __init ram_console_init().
This is often because ram_console_driver_probe lacks a __init
annotation or the annotation of ram_console_init is wrong.

Mark ram_console_driver_probe() as __devinit because it's a probe
function and propagate the __devinit markings to the __init
functions the probe calls.

Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>