Remove the bogus rules for 'lor 2' and 'str 2'.

These instructions would load or store the EM heap pointer.  They
don't work.  Programs must use brk() or sbrk() in libsys.

The last file to use 'lor 2' and 'str 2' was lang/pc/libpc/sav.e in
the Pascal library.  Commit c084f9f deleted the file, so we no longer
need rules 'lor 2' or 'str 2' to build the ACK.

mach/powerpc/ncg/table

@@ -1993,10 +1993,6 @@ PATTERNS
 			move SP, %a
 		yields %a
 
-	pat lor $1==2                      /* Load HP */
-		leaving
-			loe ".reghp"
-
 	pat str $1==0                      /* Store FP */
 		with GPR
 			gen
@@ -2007,10 +2003,6 @@ PATTERNS
 			gen
 				move %1, SP
 
-	pat str $1==2                      /* Store HP */
-		leaving
-			ste ".reghp"
-
 	pat loc ass $1==4                  /* Drop 4 bytes from stack */
 		with exact GPR
 			/* nop */