bootutil: Disable MCUBOOT_BOOT_MAX_ALIGN assert for non-swap modes

- Assert should be checked only for SWAP update modes.
- Allow platforms with page size >32 Bytes (e.g. LPC) to use
  MCUBoot, at least for non-SWAP update modes.

Signed-off-by: Andrej Butok <andrey.butok@nxp.com>