MAINTAINERS: adjust the file entry in INTEL PMC CORE DRIVER

MAINTAINERS: adjust the file entry in INTEL PMC CORE DRIVER

Commit 7e2f7e25f6ff ("arch: x86: add IPC mailbox accessor function and add
SoC register access") adds a new file entry referring to the non-existent
file linux/platform_data/x86/intel_pmc_ipc.h in section INTEL PMC CORE
DRIVER rather than referring to the file
include/linux/platform_data/x86/intel_pmc_ipc.h added with this commit.
Note that it was missing 'include' in the beginning.

Adjust the file reference to the intended file.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@redhat.com>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://patch.msgid.link/20250317092717.322862-1-lukas.bulwahn@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>