x86: restore correct module name for apm

The apm module were renamed to apm_32 during the merge of 32 and 64 bit
x86 which is unfortunate. As apm is 32 bit specific we like to keep the
_32 in the filename but the module should be named apm.

Fix this in the Makefile.

Reported-by: "A.E.Lawrence" <lawrence_a_e@ntlworld.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "A.E.Lawrence" <lawrence_a_e@ntlworld.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>