Change read count to 255 in Master Write-Read Cmd

Currently for master write-read command, maxIPMIWriteReadSize is defined
to 144. But, as per spec there's no limit specified on maximum read
count. So making it to 255 to read fully.

Tested:
Works fine using ipmitool command
Before:
ipmitool -I lanplus -H 10.165.7.34 -C 17 -U root -P 0penBmc raw 6 0x52
busID SlaveAddress 0x91 0x00
// Unable to send RAW command (channel=0x0 netfn=0x6 lun=0x0 cmd=0x52
rsp=0xc9): Parameter out of range

After:
ipmitool -I lanplus -H 10.165.7.34 -C 17 -U root -P 0penBmc raw 6 0x52
busID SlaveAddress 0xff 0x00
// Success

Signed-off-by: Joshi-Mansi <mansi.joshi@linux.intel.com>
Change-Id: I29fb826418811d44cff1e60524572f81a0b8abff
1 file changed