i386: Use "movl main@GOT(%ebx), %eax" in start.S

Don't use "leal main@GOTOFF(%ebx), %eax" since main may be in a
shared object.  Linker will convert "movl main@GOT(%ebx), %eax"
to "leal main@GOTOFF(%ebx), %eax" if main is defined locally.

	* sysdeps/i386/start.S: Replace "leal main@GOT(%ebx), %eax" with
	"movl main@GOTOFF(%ebx), %eax".