powerpc: boot: Remove leading zero in label in udelay()

When building powerpc configurations in linux-5.4.y with binutils 2.43
or newer, there is an assembler error in arch/powerpc/boot/util.S:

  arch/powerpc/boot/util.S: Assembler messages:
  arch/powerpc/boot/util.S:44: Error: junk at end of line, first unrecognized character is `0'
  arch/powerpc/boot/util.S:49: Error: syntax error; found `b', expected `,'
  arch/powerpc/boot/util.S:49: Error: junk at end of line: `b'

binutils 2.43 contains stricter parsing of certain labels [1], namely
that leading zeros are no longer allowed. The GNU assembler
documentation already somewhat forbade this construct:

  To define a local label, write a label of the form 'N:' (where N
  represents any non-negative integer).

Eliminate the leading zero in the label to fix the syntax error. This is
only needed in linux-5.4.y because commit 8b14e1dff067 ("powerpc: Remove
support for PowerPC 601") removed this code altogether in 5.10.

Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=226749d5a6ff0d5c607d6428d6c81e1e7e7a994b

 [1]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>