bnx2: remove deadcode in bnx2_init_cpus()

bnx2: remove deadcode in bnx2_init_cpus()

The load_cpu_fw function has no error return code
and always returns zero. Checking the value returned by
this function does not make sense.
Now checking the value of the return value is misleading when reading
the code. Path with error handling was deleted in 57579f7629a3
("bnx2: Use request_firmware()").
As a result, bnx2_init_cpus() will also return only zero
Therefore, it will be safe to change the type of functions
to void and remove checking to improving readability.

Found by Security Code and Linux Verification
Center (linuxtesting.org) with SVACE

Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Maxim Korotkov <korotkov.maxim.s@gmail.com>
Link: https://lore.kernel.org/r/20230322162843.3452-1-korotkov.maxim.s@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>