Uart0 Interrupt Priority bit name

PS0 is missing in c8051f120.h

I suggest adding PS0 as an alternate for PS (UART0
Interrupt priority), thus...

__sbit __at (0xBC) PS0; /* UART0 Interrupt priority
*/
__sbit __at (0xBC) PS; /* Alternate name */

Precedence is set as both ES and ES0 are already
defined in c8051f120.h

Some may say this is a feature request, not a bug,
but SiLabs calls this bit PS0 (not PS) in the same
way that the interrupt enable bit is called ES0 (not
ES). Ref SiLabs datasheet for C8051F12x-13x, Rev.
1.3, figure 11.

ES and PS ought to be retained for backward
compatibility.

The following files are similarly missing PS0
(references are to SiLabs datasheets)
c8051f020.h (ref C8051F020/1/2/3 Rev 1.4, Fig 12.10)
c8051f040.h (ref C8051F040/1/2/3/4/5/6/7 Rev 1.5,
Fig 12.12)
c8051f060.h (ref C8051F060/1/2/3/4/5/6/7 Rev 1.2,
Fig 13.20)

Steven