davinci, mmc: fix gcc 4.6 build warnings

davinci, mmc: fix gcc 4.6 build warnings

Fix:
davinci_mmc.c: In function 'dmmc_wait_fifo_status':
davinci_mmc.c:72:7: warning: variable 'mmcstatus1' set but not used [-Wunused-but-set-variable]
davinci_mmc.c: In function 'dmmc_busy_wait':
davinci_mmc.c:89:7: warning: variable 'mmcstatus1' set but not used [-Wunused-but-set-variable]

Delete the unused variable.

Signed-off-by: Heiko Schocher <hs@denx.de>
Cc: Sandeep Paulraj <s-paulraj@ti.com>
Cc: Albert ARIBAUD <albert.u.boot@aribaud.net>