spi_fpga_init: fix slab corruption bug

spi_fpga_init: fix slab corruption bug

fix this bug:
[   74.920000] bt turn on power
bcm4329
patch_plus -d /etc/bluez/bcm4325/BCM4329B1_TestOnly_0237_26MHz_SEMCO_B23.hcd /dev/ttySPI0 bcm4325 1500000
speed of uart to :1500000
[   75.330000] uart->index=0
[   75.330000] baud=115200,quot=0x34
[   75.340000] baud=115200,quot=0x34
[   75.340000] Slab corruption: size-32 start=cc3b3660, len=32
[   75.340000] 010: 6b 6b 6b 6b b4 36 3b cc 6b 6b 6b 6b 6b 6b 6b a5
[   75.370000] Prev obj: start=cc3b3640, len=32
[   75.370000] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
[   75.370000] 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5
[   75.370000] Next obj: start=cc3b3680, len=32
[   75.370000] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
[   75.370000] 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5