drivers/flash/soc_flash_nios2_qspi.c: WARNING: Unsigned expression compared with zero

[himanshujha199640]

Found using Coccinelle
#11132

himanshu@himanshu-Vostro-3559:~/zephyr$ ./scripts/coccicheck --mode=report --cocci=scripts/coccinelle/unsigned_lesser_than_zero.cocci --verbose=1 drivers/flash/soc_flash_nios2_qspi.c

Please check for false positives in the output before submitting a patch.
When using "patch" mode, carefully review the patch before submitting it.

Processing unsigned_lesser_than_zero.cocci
with option(s) ""

Message example to submit a patch:
 Unsigned expressions cannot be lesser than zero. Presence of
 comparisons 'unsigned (<|<=) 0' often indicates a bug,
 usually wrong type of variable.

 The semantic patch that makes this report is available
 in scripts/coccinelle/unsigned_lesser_than_zero.cocci.

 More information about semantic patching is available at
 http://coccinelle.lip6.fr/

Running (4 in parallel): /usr/local/bin/spatch -D report --no-show-diff --very-quiet --cocci-file scripts/coccinelle/unsigned_lesser_than_zero.cocci --patch /home/himanshu/zephyr --dir drivers/flash/soc_flash_nios2_qspi.c --jobs 4 --chunksize 1
drivers/flash/soc_flash_nios2_qspi.c:90:7-23: WARNING: Unsigned expression compared with zero.
drivers/flash/soc_flash_nios2_qspi.c:283:6-22: WARNING: Unsigned expression compared with zero.

[ramakrishnapallala]

closed as prt of #11863