[pvmfw] Move utility functions/consts relating to memory to vmbase

This cl moves some utility functions and constants relating to
memory aligment computation from pvmfw to vmbase for reuse in
rialto in the future.
No behavior change in this cl.

Bug: 284462758
Test: m pvmfw_img
Change-Id: I0ac7350c884ff00dd9379f736e9245aa39ed0b7a
diff --git a/pvmfw/src/entry.rs b/pvmfw/src/entry.rs
index 762b88b..6319863 100644
--- a/pvmfw/src/entry.rs
+++ b/pvmfw/src/entry.rs
@@ -33,7 +33,11 @@
 use log::info;
 use log::warn;
 use log::LevelFilter;
-use vmbase::{console, layout, logger, main, power::reboot};
+use vmbase::{
+    console, layout, logger, main,
+    memory::{SIZE_2MB, SIZE_4KB},
+    power::reboot,
+};
 use zeroize::Zeroize;
 
 #[derive(Debug, Clone)]
@@ -84,7 +88,7 @@
 impl<'a> MemorySlices<'a> {
     fn new(fdt: usize, kernel: usize, kernel_size: usize) -> Result<Self, RebootReason> {
         // SAFETY - SIZE_2MB is non-zero.
-        const FDT_SIZE: NonZeroUsize = unsafe { NonZeroUsize::new_unchecked(helpers::SIZE_2MB) };
+        const FDT_SIZE: NonZeroUsize = unsafe { NonZeroUsize::new_unchecked(SIZE_2MB) };
         // TODO - Only map the FDT as read-only, until we modify it right before jump_to_payload()
         // e.g. by generating a DTBO for a template DT in main() and, on return, re-map DT as RW,
         // overwrite with the template DT and apply the DTBO.
@@ -409,7 +413,7 @@
                 Some(Self::Config(config.unwrap()))
             }
             AppendedConfigType::NotFound if cfg!(feature = "legacy") => {
-                const BCC_SIZE: usize = helpers::SIZE_4KB;
+                const BCC_SIZE: usize = SIZE_4KB;
                 warn!("Assuming the appended data at {:?} to be a raw BCC", data.as_ptr());
                 Some(Self::LegacyBcc(&mut data[..BCC_SIZE]))
             }