uio: uio_fsl_elbc_gpcm:: Add null pointer check to uio_fsl_elbc_gpcm_probe

uio: uio_fsl_elbc_gpcm:: Add null pointer check to uio_fsl_elbc_gpcm_probe

[ Upstream commit d48fb15e6ad142e0577428a8c5028136e10c7b3d ]

devm_kasprintf() returns a pointer to dynamically allocated memory
which can be NULL upon failure.

Fixes: d57801c45f53e ("uio: uio_fsl_elbc_gpcm: use device-managed allocators")
Signed-off-by: Li Qiang <liqiang01@kylinos.cn>
Link: https://patch.msgid.link/20251015064020.56589-1-liqiang01@kylinos.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>