x86: quark: MRC codes clean up

x86: quark: MRC codes clean up

This patch cleans up the quark MRC codes coding style by:
- Remove BIT0/1../31 defines from mrc_util.h
- Create names for the documented BITs and use them
- For undocumented single BITs, use (1 << n) directly
- For undocumented ORed BITs, use the hex number directly
- Remove redundancy parenthesis all over the codes
- Replace to use lower case hex numbers

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>