arch: arm: boot: dts: Correct vendor-prefix for iio device isl29028 in compatible property

This patch corrects the vendor-prefix for isl29028 in the compatible property from
"isil,isl29028" to "isl,isl29028" according to listed vendor-prefixes in
Documentation/devicetree/bindings/vendor-prefixes.txt. Incorrect vendor-prefix "isl"
was reported by checkpatch.pl warning for drivers/staging/iio/light/isl29028.c.
Thus incorrect vendor-prefix "isil" was corrected for every mention of device isl29028.

Signed-off-by: Darshana Padmadas <darshanapadmadas@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>