tests/mem_protect: Adjust backing store size

This test is failing; perhaps we've shrunk the kernel enough to change what
this value needs to be?

Signed-off-by: Keith Packard <[email protected]>

Author: keith-packard

tests/kernel/mem_protect/demand_paging/mem_map/boards/qemu_x86_tiny.conf

@@ -5,7 +5,7 @@
 # However, specifying how many pages used by
 # the backing store must be done in build time.
 # So here we are, tuning this manually.
-CONFIG_BACKING_STORE_RAM_PAGES=12
+CONFIG_BACKING_STORE_RAM_PAGES=10
 
 # The following is needed so that .text and following
 # sections are present in physical memory to test