i2c: microchip: pci1xxxx: Fix comparison of -EPERM against an unsigned variable

i2c: microchip: pci1xxxx: Fix comparison of -EPERM against an unsigned variable

The comparison of variable ret with -EPERM is always false because
ret is an u8 type. Fix this by making ret an int.

Cleans up clang warning:
drivers/i2c/busses/i2c-mchp-pci1xxxx.c:714:10: warning: result of comparison
of constant -1 with expression of type 'u8' (aka 'unsigned char') is always
false [-Wtautological-constant-out-of-range-compare]

Fixes: 361693697249 ("i2c: microchip: pci1xxxx: Add driver for I2C host controller in multifunction endpoint of pci1xxxx switch")
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>