arm: tegra: fix compilation of board-harmony.c

The patch "ARM: Remove DISCONTIGMEM support" removed the node id from
the meminfo struct and the PHYS_TO_NID macro, causing compilation errors:

arch/arm/mach-tegra/board-harmony.c: In function 'tegra_harmony_fixup':
arch/arm/mach-tegra/board-harmony.c:94: error: 'struct membank' has no member named 'node'
arch/arm/mach-tegra/board-harmony.c:94: error: implicit declaration of function 'PHYS_TO_NID'
arch/arm/mach-tegra/board-harmony.c:97: error: 'struct membank' has no member named 'node'

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Colin Cross <ccross@google.com>