mips: mipssim: Renovate coding style

mips: mipssim: Renovate coding style

The script checkpatch.pl located in scripts folder was
used to detect all errors and warrnings in files:
    hw/mips/mips_mipssim.c
    hw/net/mipsnet.c

All these mips mipssim machine files were edited and
all the errors and warrings generated by the checkpatch.pl
script were corrected and then the script was
ran again to make sure there are no more errors and warnings.

Signed-off-by: Filip Bozuta <Filip.Bozuta@rt-rk.com>
Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Reviewed-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Message-Id: <1575640687-20744-4-git-send-email-Filip.Bozuta@rt-rk.com>