mmc: Change behavior when fex have not valid sdio section

Fix oops when I tryed load bcm4330.ko wich not present in my hw
configuration:

    [  428.020000] [mmc_pm]: No sdio card, please check your config !!
    [  428.020000] Config Error: not for huawei mw269x sdio wifi module
    [  428.020000] [mmc_pm]: No sdio card, please check your config !!
    [  428.030000] kernel BUG at drivers/mmc/sunxi-host/host_op.c:585!
    [  428.050000] Unable to handle kernel NULL pointer dereference at virtual address 00000000
    [  428.060000] pgd = d7a4c000
    [  428.070000] [00000000] *pgd=52d15831, *pte=00000000, *ppte=00000000
    [  428.080000] Internal error: Oops: 817 [#1] PREEMPT
    [  428.080000] Modules linked in: bcm4330(+) mali ump
    [  428.080000] CPU: 0    Not tainted  (3.0.62+ #2)
    [  428.080000] PC is at __bug+0x24/0x30
    [  428.080000] LR is at __schedule+0x2f4/0x58c
    [  428.080000] pc : [<c00393ec>]    lr : [<c04f5bd4>]    psr: 400f0013
    [  428.080000] sp : d2d03e48  ip : d2d03cd8  fp : d2d03e54
    [  428.080000] r10: bf06a000  r9 : c0089864  r8 : bf05b074
    [  428.080000] r7 : d2d02000  r6 : c0739b80  r5 : bf05b150  r4 : 00000002
    [  428.080000] r3 : 00000000  r2 : d2d02000  r1 : 00000002  r0 : 00000049
mmc: Change error behavior on invalid function parameters

sdxc_prepare_pio handle invalid parameners in unusual way - it crash
even when only one caller have error handling.