pstore: Update Documentation/android.txt

Update Documentation/android.txt to reference PSTORE_CONSOLE
and PSTORE_RAM instead of ANDROID_RAM_CONSOLE

Change-Id: I2c56e73f8c65c3ddbe6ddbf1faadfacb42a09575
Reported-by: Jon Medhurst (Tixy) <tixy@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>