ANDROID: 16K: Remove androidboot from page_shift kernel param

androidboot.page_shift was originally named this way since init
creates ro sys props for all the androidboot parameters. But it
really is a kernel command line option not a bootconfig option.
The sys prop is not currently used in the platform.

Rename 'androidboot.page_shift' to just 'page_shift' as VTS will
fail if there are androidboot* options found in the kernel command
line and not in bootconfig.

Bug: 356439363
Test: atest VtsBootconfigTest
Change-Id: Ie3e895525a9ca21ed2b3d3a39db75206a33b1cdc
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>