spi: bcm2835aux: Restore err assignment in bcm2835aux_spi_probe

spi: bcm2835aux: Restore err assignment in bcm2835aux_spi_probe

Clang warns:

drivers/spi/spi-bcm2835aux.c:532:50: warning: variable 'err' is
uninitialized when used here [-Wuninitialized]
                dev_err(&pdev->dev, "could not get clk: %d\n", err);
                                                               ^~~
./include/linux/dev_printk.h:112:32: note: expanded from macro 'dev_err'
        _dev_err(dev, dev_fmt(fmt), ##__VA_ARGS__)
                                      ^~~~~~~~~~~
drivers/spi/spi-bcm2835aux.c:495:9: note: initialize the variable 'err'
to silence this warning
        int err;
               ^
                = 0
1 warning generated.

Restore the assignment so that the error value can be used in the
dev_err statement and there is no uninitialized memory being leaked.

Fixes: e13ee6cc4781 ("spi: bcm2835aux: Fix use-after-free on unbind")
Link: https://github.com/ClangBuiltLinux/linux/issues/1199
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Link: https://lore.kernel.org/r/20201113180701.455541-1-natechancellor@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>