mmc: core: Fix switch on gp3 partition

Commit e7794c14 ("mmc: rpmb: fixes pause retune on all RPMB
partitions.") added a mask check for 'part_type', but the mask used was
wrong leading to the code intended for rpmb also being executed for GP3.

On some MMCs (but not all) this would make gp3 partition inaccessible:
armadillo:~# head -c 1 < /dev/mmcblk2gp3
head: standard input: I/O error
armadillo:~# dmesg -c
[  422.976583] mmc2: running CQE recovery
[  423.058182] mmc2: running CQE recovery
[  423.137607] mmc2: running CQE recovery
[  423.137802] blk_update_request: I/O error, dev mmcblk2gp3, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 4 prio class 0
[  423.237125] mmc2: running CQE recovery
[  423.318206] mmc2: running CQE recovery
[  423.397680] mmc2: running CQE recovery
[  423.397837] blk_update_request: I/O error, dev mmcblk2gp3, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[  423.408287] Buffer I/O error on dev mmcblk2gp3, logical block 0, async page read

the part_type values of interest here are defined as follow:
main  0
boot0 1
boot1 2
rpmb  3
gp0   4
gp1   5
gp2   6
gp3   7

so mask with EXT_CSD_PART_CONFIG_ACC_MASK (7) to correctly identify rpmb

Fixes: e7794c14 ("mmc: rpmb: fixes pause retune on all RPMB partitions.")
Cc: stable@vger.kernel.org
Cc: Jorge Ramirez-Ortiz <jorge@foundries.io>
Signed-off-by: Dominique Martinet <dominique.martinet@atmark-techno.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240306-mmc-partswitch-v1-1-bf116985d950@codewreck.org


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>