scsi: qla4xxx: shut up warning for rd_reg_indirect

The qla4_83xx_rd_reg_indirect() function can fail when it is unable to
read a register, but not all callers check its return value before using
the register data, and gcc correctly warns about this:

qla4xxx/ql4_83xx.c: In function 'qla4_83xx_process_reset_template':
qla4xxx/ql4_83xx.c:1073:36: warning: 'value' may be used uninitialized in this function
     ha->reset_tmplt.array[index++] = value;
                                    ^
qla4xxx/ql4_83xx.c:1050:11: note: 'value' was declared here
  uint32_t value;
           ^
qla4xxx/ql4_83xx.c:902:8: warning: 'value' may be used uninitialized in this function
  value &= p_rmw_hdr->test_mask;
        ^
qla4xxx/ql4_83xx.c:895:11: note: 'value' was declared here
  uint32_t value;
           ^
In file included from ../include/linux/io.h:25:0,
                 from ../include/linux/pci.h:31,
                 from ../drivers/scsi/qla4xxx/ql4_def.h:16,
                 from ../drivers/scsi/qla4xxx/ql4_83xx.c:10:
asm/io.h:101:2: warning: 'value' may be used uninitialized in this function
  asm volatile("str %1, %0"
  ^
qla4xxx/ql4_83xx.c:874:11: note: 'value' was declared here
  uint32_t value;
           ^

Unfortunately, I don't see any helpful way to add proper error handling
for this case, and the failure scenario for rd_reg seems rather obscure,
so this bails out and makes the rd_reg accessor set the result to
0xffffffff so we at least get a predictable value.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Nilesh Javali <nilesh.javali@qlogic.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>