p1-common: memory: read only 1 page at a time

By default, the Linux kernel swaps in 8 pages of memory at a time.
When using ZRAM, the incremental cost of reading 1 page at a time is
negligible and may help in case the device is under extreme memory pressure.

http://source.android.com/devices/low-ram.html

Signed-off-by: Humberto Borba <humberos@gmail.com>
Change-Id: Ie63edfaaed4a0e4841c749fd772b4a2cf5669fac