powerpc: boot: Fix kernel-doc param for partial_decompress

Fix the kernel-doc annotation for the 'skip' parameter in the
partial_decompress() function by adding a missing underscore and colon.
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240408083916.123369-1-yang.lee@linux.alibaba.com

arch/powerpc/boot/decompress.c

@@ -101,7 +101,7 @@ static void print_err(char *s)
  * @input_size:  length of the input buffer
  * @outbuf:      output buffer
  * @output_size: length of the output buffer
- * @skip         number of output bytes to ignore
+ * @_skip:       number of output bytes to ignore
  *
  * This function takes compressed data from inbuf, decompresses and write it to
  * outbuf. Once output_size bytes are written to the output buffer, or the