davinci: remove unused variable in arch/arm/mach-davinci/board-sffsdr.c

This patch fixes the following warning:

arch/arm/mach-davinci/board-sffsdr.c:99: warning: 'sffsdr_emac_pdata' defined but not used

Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>