ipmi: increase KCS timeouts

We currently time out and retry KCS transactions after 1 second of waiting
for IBF or OBF. This appears to be too short for some hardware. The IPMI
spec says "All system software wait loops should include error timeouts.
For simplicity, such timeouts are not shown explicitly in the flow
diagrams. A five-second timeout or greater is recommended". Change the
timeout to five seconds to satisfy the slow hardware.

Signed-off-by: Matthew Garrett <[e-mail]>
Signed-off-by: Corey Minyard <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/char/ipmi/ipmi_kcs_sm.c

···
 #define MAX_KCS_WRITE_SIZE IPMI_MAX_MSG_LENGTH
 
 /* Timeouts in microseconds. */
-#define IBF_RETRY_TIMEOUT 1000000
-#define OBF_RETRY_TIMEOUT 1000000
+#define IBF_RETRY_TIMEOUT 5000000
+#define OBF_RETRY_TIMEOUT 5000000
 #define MAX_ERROR_RETRIES 10
 #define ERROR0_OBF_WAIT_JIFFIES (2*HZ)