staging: rtlwifi: Use proper enum for return in halmac_parse_psd_data_88xx

Clang warns:

drivers/staging/rtlwifi/halmac/halmac_88xx/halmac_func_88xx.c:2472:11:
warning: implicit conversion from enumeration type 'enum
halmac_cmd_process_status' to different enumeration type 'enum
halmac_ret_status' [-Wenum-conversion]
                        return HALMAC_CMD_PROCESS_ERROR;
                        ~~~~~~ ^~~~~~~~~~~~~~~~~~~~~~~~
1 warning generated.

Fix this by using the proper enum for allocation failures,
HALMAC_RET_MALLOC_FAIL, which is used in the rest of this file.

Fixes: e4b08e16

 ("staging: r8822be: check kzalloc return or bail")
Link: https://github.com/ClangBuiltLinux/linux/issues/375
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>