wl12xx: spi: use dev_err instead of wl1271_error

To prevent a useless dependency between the spi module and the wl12xx
module, we need to replace the wl1271_error macros with dev_err.

At the same time, remove the SPI data hexdump, since this produces way
too much data and is not particularly useful.  There's no
print_hex_dump() equivalent for dynamic debug, so it's hard to control
when the dumps are printed out.

Signed-off-by: Luciano Coelho <coelho@ti.com>