In mach-omap1/mailbox.c the mailbox name is .name = "DSP"
while in plat-omap/dsp/dsp_core.c function  dsp_mbox_init()
asks for "dsp". This results in a strcmp() mismatch and then
OMAP1 system crashes due to NULL pointer. OMAP2 is correct,
there .name is "dsp". Correct OMAP1 name to "dsp" as well.

Signed-off-by: Dirk Behme <dirk.behme_at_gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>