spi: core: Initialize returned status in spi_setup

The previous commit that made bits-per-word validation conditional
results in leaving no unconditional affectation of the status variable.

Since the variable is returned at the end of the function, initialize
it to avoid returning an undefined value.

Signed-off-by: Paul Kocialkowski <[e-mail]>
Fixes: b3fe2e516741 ("spi: core: Only check bits_per_word validity when explicitly provided")
Reported-by: Dan Carpenter <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

drivers/spi/spi.c

···
 int spi_setup(struct spi_device *spi)
 {
 	unsigned	bad_bits, ugly_bits;
-	int		status;
+	int		status = 0;
 
 	/*
 	 * Check mode to prevent that any two of DUAL, QUAD and NO_MOSI/MISO