Use ARRAY_SIZE() macro in i386 relocs.c file

Change the explicit code in the relocs.c file to use ARRAY_SIZE()
and add a definition of ARRAY_SIZE() since this is a userspace program
and wouldn't include kernel.h.

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>