regulator: gpio: Fix the out-of-bounds access to drvdata::gpiods

regulator: gpio: Fix the out-of-bounds access to drvdata::gpiods

drvdata::gpiods is supposed to hold an array of 'gpio_desc' pointers. But
the memory is allocated for only one pointer. This will lead to
out-of-bounds access later in the code if 'config::ngpios' is > 1. So
fix the code to allocate enough memory to hold 'config::ngpios' of GPIO
descriptors.

While at it, also move the check for memory allocation failure to be below
the allocation to make it more readable.

Cc: stable@vger.kernel.org # 5.0
Fixes: d6cd33ad7102 ("regulator: gpio: Convert to use descriptors")
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://patch.msgid.link/20250703103549.16558-1-mani@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>