Do no error out if the image base address is not 0x0

Now that we compute the length of the ELF in memory based on the
last runtime address of the ELF loaded in memory, we no longer
have to worry about base addresses not being `0x0`.

Signed-off-by: Sergiu Moga <sergiu@unikraft.io>
Approved-by: Razvan Deaconescu <razvand@unikraft.io>
Reviewed-by: Michalis Pappas <michalis@unikraft.io>
GitHub-Closes: #64

elf_load.c

@@ -202,14 +202,6 @@ static int elf_load_parse(struct elf_prog *elf_prog, Elf *elf)
 	uk_pr_debug("%s: base: pie + 0x%"PRIx64", len: 0x%"PRIx64"\n",
 		    elf_prog->name, elf_prog->lowerl, elf_prog->upperl - elf_prog->lowerl);
 
-	/* We do not support yet an img base other than 0 */
-	if (unlikely(elf_prog->lowerl != 0)) {
-		elferr_err("%s: Image base is not 0x0, unsupported\n",
-			   elf_prog->name);
-		ret = -ENOEXEC;
-		goto err_out;
-	}
-
 	elf_prog->phdr.off = ehdr.e_phoff;
 	elf_prog->phdr.num = ehdr.e_phnum;
 	elf_prog->phdr.entsize = ehdr.e_phentsize;