This patch adds a call to flush_dcache_range() to bootcount_store() to
make sure, that the bootcounter data (including the patterns) is
written to memory. Without this, platforms with dcache enabled may not
have the bootcounter updated upon reset.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Valentin Longchamp <valentin.longchamp@keymile.com>