spi: s3c64xx: fix timeout counters in flush_fifo

In the s3c64xx_flush_fifo() code, the loops counter is post-decremented
in the do { } while(test && loops--) condition. This means the loops is
left at the unsigned equivalent of -1 if the loop times out. The test
after will never pass as if tests for loops == 0.

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Fixes: 230d42d4 ("spi: Add s3c64xx SPI Controller driver")
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://patch.msgid.link/20240924134009.116247-2-ben.dooks@codethink.co.uk


Signed-off-by: Mark Brown <broonie@kernel.org>