mmc: be more verbose about card insertions/removal

Let the user know that the kernel actually detected the card
by printing some basic information in dmesg.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

diff --cc drivers/mmc/core/bus.c
Simple merge

diff --cc drivers/mmc/core/mmc.c
Simple merge

diff --cc drivers/mmc/core/sd.c
Simple merge