net: ethernet: ti: Fix format specifier in netcp_create_interface()

After commit 3948b059 ("net: introduce a config option to tweak
MAX_SKB_FRAGS"), clang warns:

  drivers/net/ethernet/ti/netcp_core.c:2085:4: warning: format specifies type 'long' but the argument has type 'int' [-Wformat]
                          MAX_SKB_FRAGS);
                          ^~~~~~~~~~~~~
  include/linux/dev_printk.h:144:65: note: expanded from macro 'dev_err'
          dev_printk_index_wrap(_dev_err, KERN_ERR, dev, dev_fmt(fmt), ##__VA_ARGS__)
                                                                 ~~~     ^~~~~~~~~~~
  include/linux/dev_printk.h:110:23: note: expanded from macro 'dev_printk_index_wrap'
                  _p_func(dev, fmt, ##__VA_ARGS__);                       \
                               ~~~    ^~~~~~~~~~~
  include/linux/skbuff.h:352:23: note: expanded from macro 'MAX_SKB_FRAGS'
  #define MAX_SKB_FRAGS CONFIG_MAX_SKB_FRAGS
                        ^~~~~~~~~~~~~~~~~~~~
  ./include/generated/autoconf.h:11789:30: note: expanded from macro 'CONFIG_MAX_SKB_FRAGS'
  #define CONFIG_MAX_SKB_FRAGS 17
                               ^~
  1 warning generated.

Follow the pattern of the rest of the tree by changing the specifier to
'%u' and casting MAX_SKB_FRAGS explicitly to 'unsigned int', which
eliminates the warning.

Fixes: 3948b059

 ("net: introduce a config option to tweak MAX_SKB_FRAGS")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20230329-net-ethernet-ti-wformat-v1-1-83d0f799b553@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>