docs: ipmi: fix spelling and grammar mistakes

Corrected various spelling and grammatical mistakes in
Documentation/driver-api/ipmi.rst to improve readability.

No changes to the technical content has been made.

Signed-off-by: Praveen Balakrishnan <praveen.balakrishnan@magd.ox.ac.uk>
Message-ID: <20250515234757.19710-1-praveen.balakrishnan@magd.ox.ac.uk>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Corey Minyard <corey@minyard.net>