x86: linker: Maintain 4K alignment for application memory.

When MMU is enabled and the SOC we are running doesn't have
execute in-place(XIP) the final image will be a monolith which
sits in RAM. In such situations we need to maintain the alignment
for application memory. If not maintained the MMU boot tables
will not be configured properly.

Signed-off-by: Adithya Baglody <adithya.nagaraj.baglody@intel.com>