[uaccess] Remove redundant memcpy_user() and related string functions

The memcpy_user(), memmove_user(), memcmp_user(), memset_user(), and
strlen_user() functions are now just straightforward wrappers around
the corresponding standard library functions.

Remove these redundant wrappers.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/image/elf.c

@@ -66,7 +66,7 @@ static int elf_load_segment ( struct image *image, Elf_Phdr *phdr,
 	}
 
 	/* Copy image to segment */
-	memcpy_user ( buffer, 0, image->data, phdr->p_offset, phdr->p_filesz );
+	memcpy ( buffer, ( image->data + phdr->p_offset ), phdr->p_filesz );
 
 	return 0;
 }

src/image/segment.c

@@ -83,7 +83,7 @@ int prep_segment ( userptr_t segment, size_t filesz, size_t memsz ) {
 		if ( ( start >= memmap.regions[i].start ) &&
 		     ( end <= memmap.regions[i].end ) ) {
 			/* Found valid region: zero bss and return */
-			memset_user ( segment, filesz, 0, ( memsz - filesz ) );
+			memset ( ( segment + filesz ), 0, ( memsz - filesz ) );
 			return 0;
 		}
 	}