omap: dsp: remove shm from normal memory

Also, don't be picky about the location, which incidentally fixes the
build since MEMBLOCK_REAL_LIMIT is gone on 2.6.37.

arch/arm/plat-omap/devices.c: In function 'omap_dsp_reserve_sdram_memblock':
arch/arm/plat-omap/devices.c:287: error: 'MEMBLOCK_REAL_LIMIT'
    undeclared (first use in this function)

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Omar Ramirez Luna <omar.ramirez@ti.com>