spi/s3c64xx: improve error handling
spi/s3c64xx: improve error handling

When a device tree definition os an s3c64xx SPI master is missing
a "controller-data" subnode, the newly added s3c64xx_get_slave_ctrldata
function might use uninitialized memory in place of that node,
which was correctly reported by gcc.

Without this patch, building s3c6400_defconfig results in:

drivers/spi/spi-s3c64xx.c: In function 's3c64xx_get_slave_ctrldata.isra.25':
drivers/spi/spi-s3c64xx.c:841:5: warning: 'data_np' may be used uninitialized in this function [-Wuninitialized]

Signed-off-by: Arnd Bergmann <f2c659f01951776204a6c5b902787d9019fbeebd@arndb.de>
Acked-by: Thomas Abraham <f8cb4d3099c555ac2fa0712396a78d2cd666d4bd@linaro.org>
Acked-by: Kukjin Kim <3fc711f4e08bc570a586748633ff7c76d0e1e253@samsung.com>
Cc: Jaswinder Singh <191fbc354bb0d45dfb103e8f4f6583bfe2bb3ef7@linaro.org>
Cc: Grant Likely <9069e6f5a2b566e2674a0ba1e2bf39c12c195fad@secretlab.ca>

KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs