m68k/hp300: Export hp300_ledstate

The accidental loss of CONFIG_DIO in commit
0e152d8050 ("m68k: reorganize Kconfig options
to improve mmu/non-mmu selections") exposed a missing symbol export in
m68k allmodconfig.  If CONFIG_HP300=y but CONFIG_HPLANCE (which is bool,
and depends on CONFIG_DIO) is not set, and CONFIG_MVME147=y and
CONFIG_MVME147_NET=m, 7990.c is compiled as a module, giving:

ERROR: "ledstate" [drivers/net/ethernet/amd/7990.ko] undefined!

Add the missing export, and rename ledstate to hp300_ledstate while we're
at it, as it's a too generic name.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

arch/m68k/hp300/config.c

@@ -24,7 +24,8 @@
 
 unsigned long hp300_model;
 unsigned long hp300_uart_scode = -1;
-unsigned char ledstate;
+unsigned char hp300_ledstate;
+EXPORT_SYMBOL(hp300_ledstate);
 
 static char s_hp330[] __initdata = "330";
 static char s_hp340[] __initdata = "340";