drivers: eswifi: fix spi initialization

This change reverts a portion of a prior change that results
in an uninitialized eswifi_spi_data struct to be passed to
the `is_spi_ready` function.
See commit 48c87f2bf8b768f550cfe6756d3cd313f9a02c3f

Signed-off-by: Brian Dunlay <brian.dunlay@gmail.com>
1 file changed