[PATCH] FIx crash in mmc_block on 64-bit

[Ben Collins]

Fairly simple. "dev_use" was being allocated as a zero length array
because of bad math on 64-bit systems causing a crash in
find_first_zero_bit(). One-liner follows:

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 91ded3e..f9ad960 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -46,7 +46,7 @@
 #define MMC_SHIFT	3
 #define MMC_NUM_MINORS	(256 >> MMC_SHIFT)
 
-static unsigned long dev_use[MMC_NUM_MINORS/(8*sizeof(unsigned long))];
+static DECLARE_BITMAP(dev_use, MMC_NUM_MINORS);
 
 /*
  * There is one mmc_blk_data per slot.