mtd: nand: qpic_common: use {cmd,data}_sgl_nitems for sg_init_table()

mtd: nand: qpic_common: use {cmd,data}_sgl_nitems for sg_init_table()

Since commit ddaad4ad774d ("mtd: nand: qpic_common: prevent out of
bounds access of BAM arrays"), the {cmd,data}_sgl_nitems members in
the 'bam_transaction' structure are containing the number of elements
in the cmd/data scatter-gather lists.

Change the qcom_clear_bam_transaction() function to use these numbers
while reinitializing the sg lists instead of recomputing the number of
elements to make it less error prone.

Signed-off-by: Gabor Juhos <j4g8y7@gmail.com>
Acked-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>