ARM: 8925/1: tcm: include <asm/tcm.h> for missing declarations

The arch/arm/kernel/tcm.c should include <asm/tcm.h>
for declarations of tcm_alloc, tcm_free and other
functions. Fixes the following sparse warnings:

arch/arm/kernel/tcm.c:74:6: warning: symbol 'tcm_alloc' was not declared. Should it be static?
arch/arm/kernel/tcm.c:92:6: warning: symbol 'tcm_free' was not declared. Should it be static?
arch/arm/kernel/tcm.c:98:6: warning: symbol 'tcm_dtcm_present' was not declared. Should it be static?
arch/arm/kernel/tcm.c:104:6: warning: symbol 'tcm_itcm_present' was not declared. Should it be static?

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>