Cleanups to *ERR* compat shims.

[jhb]

Summary

• Use [u]intptr_t casts to convert pointers to integers.

• Change IS_ERR* to return bool instead of long.

[jhb]

sys/compat/linuxkpi/common/include/linux/err.h

43

This could also probably stay as a long though the cast below might need adjusting for architectures where long != intptr_t.

48

Since this doesn't return valid pointers, just errors, I think I should leave this as long. It also breaks some printf strings that want to use %ld to print these values.

[jhb]

• Revert some of the earlier changes to keep error values as longs.

[jhb]

This passes make tinderbox.

[manu]

Haven't tested but looks good to me.