fix miropcm20-rds.c compilation

The removal of #include <linux/devfs_fs_kernel.h> broke the compilation of drivers/media/radio/miropcm20-rds.c.old in 2.5.68-bk11:

<-- snip -->

...
gcc-2.95 -Wp,-MD,drivers/media/radio/.miropcm20-rds.o.d -D__KERNEL__
-Iinclude -Wall -Wstrict-prototypes -Wno-trigraphs -O2 -fno-strict-aliasing -fno-common -pipe -mpreferred-stack-boundary=2 -march=k6
-Iinclude/asm-i386/mach-default -nostdinc -iwithprefix include -DKBUILD_BASENAME=miropcm20_rds
-DKBUILD_MODNAME=miropcm20_rds -c -o drivers/media/radio/miropcm20-rds.o drivers/media/radio/miropcm20-rds.c drivers/media/radio/miropcm20-rds.c:23: warning: `struct inode' declared inside parameter list
drivers/media/radio/miropcm20-rds.c:23: warning: its scope is only this definition or declaration, which is probably not what you want. drivers/media/radio/miropcm20-rds.c:38: warning: `struct inode' declared inside parameter list
drivers/media/radio/miropcm20-rds.c:106: variable rds_fops' has initializer but incomplete type drivers/media/radio/miropcm20-rds.c:107: unknown field owner' specified in initializer
drivers/media/radio/miropcm20-rds.c:107: warning: excess elements in struct initializer
drivers/media/radio/miropcm20-rds.c:107: warning: (near initialization for `rds_fops')
drivers/media/radio/miropcm20-rds.c:108: unknown field `read' specified in initializer
drivers/media/radio/miropcm20-rds.c:108: warning: excess elements in struct initializer
drivers/media/radio/miropcm20-rds.c:108: warning: (near initialization for `rds_fops')
drivers/media/radio/miropcm20-rds.c:109: unknown field `open' specified in initializer
drivers/media/radio/miropcm20-rds.c:109: warning: excess elements in struct initializer
drivers/media/radio/miropcm20-rds.c:109: warning: (near initialization for `rds_fops')
drivers/media/radio/miropcm20-rds.c:110: unknown field `release' specified in initializer drivers/media/radio/miropcm20-rds.c:111: warning: excess elements in struct initializer
drivers/media/radio/miropcm20-rds.c:111: warning: (near initialization for `rds_fops')
make[3]: *** [drivers/media/radio/miropcm20-rds.o] Error 1

<-- snip -->

The fix is simple:

@@ -13,6 +13,7 @@
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/miscdevice.h>
+#include <linux/fs.h>
 #include <asm/uaccess.h>
 #include "miropcm20-rds-core.h"
 

cu
Adrian

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed