docs: ABI: fix spelling/grammar in SBEFIFO timeout interface

Correct spelling problems as identified by codespell.
Correct one grammar error.

Fixes: 9a93de62 ("docs: ABI: testing: Document the SBEFIFO timeout interface")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Eddie James <eajames@linux.ibm.com>
Cc: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20230710052305.29611-1-rdunlap@infradead.org


Signed-off-by: Joel Stanley <joel@jms.id.au>