It's not okay to cast a "u32 *" to "unsigned long *" when you are
doing a for_each_set_bit() loop because that will break on big
endian systems.

Fixes: 386145601b82 ("mfd: stmfx: Uninitialized variable in stmfx_irq_handler()")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Tested-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

The problem is that on 64bit systems then we don't clear the higher
bits of the "pending" variable.  So when we do:

        ack = pending & ~BIT(STMFX_REG_IRQ_SRC_EN_GPIO);
        if (ack) {

the if (ack) condition relies on uninitialized data.  The fix it that
I've changed "pending" from an unsigned long to a u32.  I changed "n" as
well, because that's a number in the 0-10 range and it fits easily
inside an int.  We do need to add a cast to "pending" when we use it in
the for_each_set_bit() loop, but that doesn't cause a problem, it's
fine.

Fixes: 06252ade9156 ("mfd: Add ST Multi-Function eXpander (STMFX) core driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

STMicroelectronics Multi-Function eXpander (STMFX) is a slave controller
using I2C for communication with the main MCU. Main features are:
- 16 fast GPIOs individually configurable in input/output
- 8 alternate GPIOs individually configurable in input/output when other
STMFX functions are not used
- Main MCU IDD measurement
- Resistive touchscreen controller

Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>