scripts/spelling.txt: drop "sepc" from the misspelling list

The RISC-V architecture has a register named the "Supervisor Exception
Program Counter", or "sepc".  This abbreviation triggers checkpatch.pl's
misspelling detector, resulting in noise in the checkpatch output.  The
risk that this noise could cause more useful warnings to be missed seems
to outweigh the harm of an occasional misspelling of "spec".  Thus drop
the "sepc" entry from the misspelling list.

[akpm@linux-foundation.org: fix existing "sepc" instances, per Joe]
Link: http://lkml.kernel.org/r/20190518210037.13674-1-paul.walmsley@sifive.com
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/powerpc/kvm/book3s_xics.c

@@ -827,7 +827,7 @@ static noinline int kvmppc_h_eoi(struct kvm_vcpu *vcpu, unsigned long xirr)
 	 *
 	 * Note: If EOI is incorrectly used by SW to lower the CPPR
 	 * value (ie more favored), we do not check for rejection of
-	 * a pending interrupt, this is a SW error and PAPR sepcifies
+	 * a pending interrupt, this is a SW error and PAPR specifies
 	 * that we don't have to deal with it.
 	 *
 	 * The sending of an EOI to the ICS is handled after the